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1.	Abulaiti, Yiming, et al. (författare) Search for an invisibly decaying Higgs boson or dark matter candidates produced in association with a Z boson in pp collisions at root s=13 TeV with the ATLAS detector 2018 Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445 .- 0009-2614 .- 1873-4448. ; 776, s. 318-337 Tidskriftsartikel (refereegranskat)abstract A search for an invisibly decaying Higgs boson or dark matter candidates produced in association with a leptonically decaying Z boson in proton-proton collisions at root s = 13 TeV is presented. This search uses 36.1 fb(-1) of data collected by the ATLAS experiment at the Large Hadron Collider. No significant deviation from the expectation of the Standard Model backgrounds is observed. Assuming the Standard Model ZH production cross-section, an observed (expected) upper limit of 67% (39%) at the 95% confidence level is set on the branching ratio of invisible decays of the Higgs boson with mass m(H) = 125 GeV. The corresponding limits on the production cross-section of the ZH process with the invisible Higgs boson decays are also presented. Furthermore, exclusion limits on the dark matter candidate and mediator masses are reported in the framework of simplified dark matter models.
2.	Milstead, David A., et al. (författare) Measurement of differential cross sections of isolated-photon plus heavy-flavour jet production in pp collisions at s=8 TeV using the ATLAS detector 2018 Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693 .- 0009-2614 .- 1873-4448 .- 1873-2445. ; 776, s. 295-317 Tidskriftsartikel (refereegranskat)abstract This Letter presents the measurement of differential cross sections of isolated prompt photons produced in association with a b-jet or a c-jet. These final states provide sensitivity to the heavy-flavour content of the proton and aspects related to the modelling of heavy-flavour quarks in perturbative QCD. The measurement uses proton–proton collision data at a centre-of-mass energy of 8 TeV recorded by the ATLAS detector at the LHC in 2012 corresponding to an integrated luminosity of up to 20.2 fb−1. The differential cross sections are measured for each jet flavour with respect to the transverse energy of the leading photon in two photon pseudorapidity regions: \|ηγ\|<1.37 and 1.56<\|ηγ\|<2.37. The measurement covers photon transverse energies 25
3.	Rasmusson, M, et al. (författare) Photodissociation of bromobenzene in solution 2003 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 367:5-6, s. 759-766 Tidskriftsartikel (refereegranskat)abstract The photodissociation of bromobenzene in solution was investigated with ultrafast transient absorption spectroscopy following excitation at 266 nm. Ab initio calculations of lower singlet and triplet states were performed in order to guide the interpretations. The main feature of the kinetics measured between 300 and 930 nm in acetonitrile is a 9 +/- 1ps decay, which we mainly assign to predissociation. Similar decays were observed in hexane, dichloromethane and tetrachloromethane at 400 and 800 nm. Other features in acetonitrile, such as complicated short-time dynamics between 420 and 620 nm and a long-lived component, might indicate the involvement of lower triplet states.
4.	Salek, Pawel, et al. (författare) Dynamical suppression of atomic peaks in resonant dissociative photoemission 2001 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 343:3-4, s. 332-338 Tidskriftsartikel (refereegranskat)abstract Resonant excitation to the F1s-sigma* dissociative state in hydrogen fluoride gives a photoelectron spectrum where the spectator part contains strong atomic lines but a participator part where such lines are lacking. We demonstrate that this contrasting behaviour between the two parts is due to a strong dynamical suppression of the resonant contribution, making direct main state photoionization the dominating channel even at resonant conditions.
5.	Theander, M., et al. (författare) High luminescence from a substituted polythiophene in a solvent with low solubility 2001 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 337:4-6, s. 277-283 Tidskriftsartikel (refereegranskat)abstract Steady-state and rime-resolved photoluminescence (PL) is used to probe different states of order in highly regular poly(3-(2'-methoxy-5'-octylphenyl)thiophene) (POMeOPT). In a good solvent (chloroform) the polymer has a PL yield of 0.33 and in a solvent with low solubility (mixture of chloroform and toluene) a new phase appears with higher PL yield (0.50). The new phase is attributed to micro-crystals formed by the regular part of the polymer which have low solubility in toluene. The crystallites have highly structured and redshifted electronic transitions compared with chains which are dissolved. (C) 2001 Published by Elsevier Science B.V.
6.	Almlöf, Jan (författare) Hydrogen bond studies. 71. Ab initio calculation of the vibrational structure and equilibrium geometry in HF−2 and DF−2 1972 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 17:1, s. 49-52 Tidskriftsartikel (refereegranskat)abstract MO LCAO SCF calculations have been performed to investigate the molecular astructure and vibrational spectrum of the bifluoride ion in its normal and deuterated form. The potential energy for nuclear motions has been evaluated as a function of the molecular degrees of freedom, taking only linear geometries into account. The vibrational Schrödinger equation has been solved by expanding the vibrational part of the total wavefunction as a sum of products of linear harmonic-oscillator eigenfunctions. The calculated properties are in good agreement with experiments, and even the minute effects of deuteration are well reproduced.
7.	Andersson, Renée, et al. (författare) Photoionisation of molecular wavepackets – the NaK(C1Σ+) case 2002 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 352, s. 106-112 Tidskriftsartikel (refereegranskat)
8.	Barnes, Leslie A, et al. (författare) Symmetry breaking in O+4 : an application of the Brueckner coupled-cluster method 1994 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 223:3, s. 207-214 Tidskriftsartikel (refereegranskat)abstract A recent calculation of the antisymmetric stretch frequency for the rectangular structure of quartet O4+ using the QCISD(T) method gave a value of 3710 cin-1. This anomalous frequency is shown to be a consequence of symmetry-breaking effects, which occur even though the QCISD(T) solution derived from a delocalized SCF reference function lies energetically well below the two localized (symmetry-broken) solutions at the equilibrium geometry. The symmetry breaking is almost eliminated at the CCSD level of theory, but the small remaining symmetry-breaking effects are magnified at the CCSD (T) level of theory so that the antisymmetric stretch frequency is still significantly in error. The Brueckner coupled-cluster method, however, leads to a symmetrical solution which is free of symmetry-breaking effects, with an antisymmetric stretch frequency of 1322 cm-1, in good agreement with our earlier calculations using the CASSCF/CASSI method.
9.	Baudin, M., et al. (författare) MD simulations of a doped ceria surface - very large surface ion motion 2001 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 335:06-maj, s. 517-523 Tidskriftsartikel (refereegranskat)abstract Mean-square displacements (MSDs) and individual-ion square-displacements (ISDs) for the different constituents in Ca-doped CeO2(0 1 1) slabs at 300 K have been studied as a function of depth from the surface. Constant pressure-constant temperature MD simulations were used. The MSDs are 2-3 times larger at the surface than in the bulk, but ISDs as large as ca. 150 times the surface MSD value were observed during short-time periods for anions next to an anion vacancy at the surface. The chemical implications of this kind of motion are important, since transient structural distortions of this magnitude will lead to large electron re-distributions.
10.	Berggren, Magnus, et al. (författare) Controlling inter-chain and intra-chain excitations of a poly(thiophene) derivative in thin films 1999 Ingår i: Chemical Physics Letters. - : Elsevier. - 0009-2614 .- 1873-4448. ; 304:1-2, s. 84-90 Tidskriftsartikel (refereegranskat)abstract The decay of photoexcitations in polythiophene chains has been studied in solid solutions of the polymer from room temperature to 4 K. A strong blue shift of the emission spectrum is observed in the polymer blend, as compared to the homopolymer. Dispersion of the polythiophene suppresses the non-radiative processes, which are suggested to be correlated to close contacts of polymer chains. Quantum chemistry modeling of the excited state distributed on two chains corroborate this conclusion.
11.	Bernhardsson, Anders, et al. (författare) Direct self-consistent reaction field with Pauli repulsion : Solvation effects on methylene peroxide 1996 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 251:3-4, s. 141-149 Tidskriftsartikel (refereegranskat)abstract The properties of methylene peroxide in the gas phase and water have been examined. The solution effects have been modeled with a cavity. To make it possible to optimize the geometry of the cavity, we have added an approximate description of the Pauli repulsion between the solvent and the solute. An efficient direct implementation of the calculation of multicenter multipole operators is also described. We have applied the method to calculate the electric properties of methylene peroxide, a system that is characterized by its near degeneracy between a biradical and a zwitterionic state. As expected, it is shown that solvent effects will stabilize the ionic configuration, resulting in a considerably weakened OO bond and an increased double bond character in the CO bond. The theoretical study has been performed using the multiconfigurational (CAS) SCF method and second-order perturbation theory (CASPT2).
12.	Biglino, D., et al. (författare) Pulsed EPR study of the (NO)2-Na+ triplet state adsorption complex 2001 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 349:5-6, s. 511-516 Tidskriftsartikel (refereegranskat)abstract The (NO)2-Na+ triplet state complex stabilised in Na-A zeolites at low temperature was studied by pulsed EPR. The 3-pulse ESEEM spectra at 5 K were analysed by simulations in the time-domain, followed by Fourier transformation. The ESEEM was attributed to the interaction with Na+. The hyperfine coupling A(23Na)=(4.6, 4.6, 8.2) MHz and nuclear quadrupole Q(23Na)=(0.3, 0,3, -0.6) MHz tensors are of comparable magnitude as in the NO-Na+ complex determined earlier. The complexes are proposed to be either pairs of NO-Na+ or ON-Na+-NO.
13.	Bittererova, M., et al. (författare) Ab initio study of the ground state and the first excited state of the rectangular (D-2h) N-4 molecule 2001 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 347:03-jan, s. 220-228 Tidskriftsartikel (refereegranskat)abstract The dissociation pathway of D-2h N-4 has been investigated at the CASSCF level of theory. A new C-2v transition state to dissociation was found and characterized on the potential energy surface. The effective barrier of dissociation from D-2h N-4 to 2N(2) is estimated to 6.5 kcal/mol from MR-AQCCNTZ//CAS(12,12)/VTZ calculations. Vertical excitation energies and oscillator strengths for the lowest 20 singlet states of D-2h N-4 have been calculated using the EOM-CCSD method. The geometry of the first excited state B-1(3u), considered as the lowest optically accessible state, has been optimized and characterized at various computational levels. This state might be useful for detection of D-2h N-4 by means of laser-induced fluorescence (LIF) spectroscopy.
14.	Bittererova, M., et al. (författare) Theoretical study of the singlet electronically excited states of N-4 2001 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 340:06-maj, s. 597-603 Tidskriftsartikel (refereegranskat)abstract Vertical excitation energies for the lowest eleven singlet states of T-d N-4 were calculated using the TD-DFT method with the B3LYP functional, and at the EOM-CCSD level of theory. The vertical excitation energies for the five lowest-lying excited states were also obtained using the state-averaged CASSCF, CASPT2, CASPT3, and MRCI + Q methods. Our results show that the five lowest-lying states are of valence character. EOM-CCSD/d-aug-cc-pVTZ calculations predict that there are two weakly allowed optical transitions of T-2 symmetry at 10.44 and 10.82 eV. The transition to the third T-2 state, which is predicted to be at 10.89 eV, has an oscillator strength about one order of magnitude higher.
15.	Boschloo, Gerrit, et al. (författare) Photoinduced absorption spectroscopy of dye-sensitized nanostructured TiO2 2003 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 370:04-mar, s. 381-386 Tidskriftsartikel (refereegranskat)abstract Photoinduced absorption (PIA) spectroscopy was used to investigate dye-sensitized electrodes and solar cells under illumination conditions comparable to sunlight. In the absence of redox electrolyte, cis-Ru (dcbpy)(2)(NCS)(2)-sensitized nanostructured TiO2 films show a long-lived photoinduced charge-separation (oxidized dye molecules/injected electrons in TiO2), with a lifetime of about 10(-3) s under full sun illumination. The PIA spectrum of a complete dye-sensitized cell is due to electrons in TiO2 and iodine radicals (12) in the electrolyte. The lifetime of this charge-separated state at open-circuit conditions was determined to be 0.15 s (0.27 sun illumination).
16.	Brändas, Erkki, et al. (författare) Wave function constructed from complex hybrids 1969 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 3:5, s. 315-318 Tidskriftsartikel (refereegranskat)abstract The influence on the total wave function of an atomic basis consisting of complex hybrids is considered. The complex character of the wave function in the MO-LCAO scheme ss well as in the VB method is derived, and its consequences with respect to time reversal symmetry are discussed.
17.	Carravetta, V., et al. (författare) An ab initio method for computing multi-atom resonant photoemission 2002 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 354:02-jan, s. 100-108 Tidskriftsartikel (refereegranskat)abstract We present an ab initio method for computing multi-atom resonant photoemission (MARPE) in molecules and use this method to investigate the possibility of having a sizable MARPE effect. The MARPE cross section is obtained by making multi-center expansions of both the dipole matrix element - direct emission - and the hamiltonian matrix element between the resonant state and the autoionizing states - resonant emission. We show by sample calculations that the resonant contribution exhibits a strong distance dependence of the atoms participating in the MARPE process, and that it is energy dependent and element specific for the neighboring atoms. The ratio of resonant MARPE and direct photoionization cross sections is found to amount to less than one percent which probably makes the molecular MARPE effect difficult to apply in practice.
18.	Cronstrand, Peter, et al. (författare) Ab initio calculations of three-photon absorption 2003 Ingår i: Chemical Physics Letters. - : Elsevier. - 0009-2614 .- 1873-4448. ; 375:02-jan, s. 233-239 Tidskriftsartikel (refereegranskat)abstract We present large scale ab initio calculations of three-photon absorption of a series of dithienothiophene based charge transfer molecules using response theory within the random phase approximation. The structure-to-property relations obtained for the three-photon absorption cross-sections are discussed and compared with those for one- and two-photon absorption.
19.	Cronstrand, P., et al. (författare) Ab initio calculations of three-photon absorption 2003 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 375:1-2, s. 233-239 Tidskriftsartikel (refereegranskat)abstract We present large scale ab initio calculations of three-photon absorption of a series of dithienothiophene based charge transfer molecules using response theory within the random phase approximation. The structure-to-property relations obtained for the three-photon absorption cross-sections are discussed and compared with those for one- and two-photon absorption. © 2003 Published by Elsevier Science B.V.
20.	Cronstrand, P., et al. (författare) Generalized few-state models for two-photon absorption of conjugated molecules 2002 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 352:04-mar, s. 262-269 Tidskriftsartikel (refereegranskat)abstract We present three- and four-state models for two-photon absorption (TPA) cross-sections generalized to include dipolar direction information and polarization effects of the laser beam. By introducing an effective dipole moment which incorporates the directions of the transition dipole moments and the influence of additionally strongly coupled excited states we can distinguish between different effects leading to enhanced two-photon absorption.
21.	Derkatch, A., et al. (författare) Lifetime measurements of the A (2)Pi state of BaCl using laser spectroscopy 2000 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 332:04-mar, s. 278-282 Tidskriftsartikel (refereegranskat)abstract The lowest-lying radiative state of barium chloride has been studied by laser-induced fluorescence in the near-infrared wavelength region. The A (II1/2)-I-2 and A (II3/2)-I-2 states have been investigated in time-resolved experiments using a Ti:Sapphire laser. The zero pressure radiative lifetime measured for the e-levels of BaCl was 107 +/- 4 ns for the A (II1/2)-I-2 state and 101+/-6 ns for the A (II3/2)-I-2 state. The discrepancy between the corresponding transition moments is discussed.
22.	Edholm, O., et al. (författare) The barrier for heme-protein separation estimated by non-equilibrium molecular dynamics simulations 1998 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 291:5-6, s. 501-508 Tidskriftsartikel (refereegranskat)abstract In heme-containing proteins the heme group is usually non-covalently bound in a pocket. Molecular dynamics (MD) simulations have been performed to estimate the barrier height for heme-protein separation. In simulations of myoglobin dissolved in water, a force has been applied to pull the heme out of the binding pocket. With forces above 0.5 nN, the heme group is easily pulled out of the pocket in times of the order of tens of picoseconds. With weaker forces, heme release becomes too slow to be monitored in an MD simulation covering a couple of hundred picoseconds. These results are consistent with a free energy barrier to heme release of about 100 kJ/mol. The results show that the main energetic change that occurs during the release is a conversion of heme/protein Lennard-Jones energy into heme/water Lennard-Jones energy. The release is essentially barrierless in energy indicating that the main part of the barrier is entropic.
23.	Engstrom, Maria, et al. (författare) Ab initio g-tensor calculations of hydrogen bond effects on a nitroxide spin label 2001 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 338:06-apr, s. 407-413 Tidskriftsartikel (refereegranskat)abstract Hydrogen bonding effects on the electron paramagnetic resonance (EPR) g-tensor of a nitroxide spin label was investigated by quantum chemical calculations. The restricted open-shell Hartree-Fock (ROHF) linear response method with the atomic mean field approximation (AMFI) was used in the calculations. The results show that hydrogen bonding reduces the g-tensor component directed along the NO bond, g(xx). This decrease is traced to higher excitation energy and lower spin-orbit coupling and angular momentum matrix elements for the n-pi* excitation. The calculations show that the g-tensor is practically invariable when hydrogen bonding was modeled with methanol instead of water.
24.	Engstrom, Maria, et al. (författare) Ab initio g-tensor calculations of the thioether substituted tyrosyl radical in galactose oxidase 2000 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 319:04-mar, s. 191-196 Tidskriftsartikel (refereegranskat)abstract The tyrosyl radical in galactose oxidase is covalently cross-linked to a neighboring cysteine residue through a thioether bond. The role of this sulfur cross-link has been discussed ever since the crystal structure of the enzyme was solved. In the present work, the ab initio multiconfigurational linear response method is applied to calculate the g-tensor of unsubstituted and thioether substituted phenoxyl radicals. In contrast to some previous interpretations, but in agreement with recent EPR measurements, we find that the sulfur substitution induces only minor shifts in the g-tensor components. The spin distribution retains the odd-alternant pattern of the unsubstituted radical and only a small amount of spin is localized to the sulfur center.
25.	Engstrom, Maria, et al. (författare) MCSCF and DFT calculations of EPR parameters of sulfur centered radicals 2000 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 328:06-apr, s. 483-491 Tidskriftsartikel (refereegranskat)abstract The EPR parameters of sulfur centered radicals are different depending on the radical structure, charge and solvent. That is, the g- and A-tensor components provide significant patterns which may distinguish sulfur radical structures from each other. In the present work, these EPR parameters were calculated for monosulfide radicals (RS'), disulfide radicals (RSS.), radical cations ((RSSR+)-S-.) and anions ((RSSR-)-S-.), with R = CH3, using the MCSCF linear response and DFT/B3LYP methods. Results were in agreement with experimental data for the cases when well-resolved EPR spectra are available. Especially, the assignment of the disulfide anion in ribonucleotide reductase was confirmed. The results indicate that investigations with the present computational methods on refined structures and solvent modeling may provide interpretations of experimental data on unassigned radical species.
26.	Estreicher, S.K., et al. (författare) Stable and metastable states of C60H: buckminsterfullerene monohydride 1992 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 196:3-4, s. 311-316 Tidskriftsartikel (refereegranskat)abstract Approximate ab initio Hartree-Fock and first-principles density functional calculations of potential energy surfaces and electronic structures of C60H show that the stable state has H attached to one C atom, outside the buckyball. This C atom is displaced radially outward and is close to being sp3 hybridized. The unpaired electron of C60H is delocalized. The calculated Fermi contact density at the proton is in good agreement with recent low-temperature μSR data. A metastable configuration has atomic H at the center of the ball (H@C60). Once trapped there, H must overcome a large barrier to go through the surface of C60. Other configurations we considered include H attached to one C atom but inside the buckyball, and H bridging one of the two inequivalent CC bonds. The barrier for diffusion of H from outside to the center of C60 have also been calculated. The results are compared to recent muon spin rotation studies in solid C60 and to the states of hydrogen in other forms of carbon.
27.	Fauquet, C., et al. (författare) Electronic structure of trimethylamine alane in the solid state 1995 Ingår i: Chemical Physics Letters. - : Elsevier. - 0009-2614 .- 1873-4448. ; 235:5-6, s. 528-534 Tidskriftsartikel (refereegranskat)abstract The chemical and electronic structure of ultrathin molecular films of trimethylamine alane (TMAA), condensed in UHV at âˆ’ 100Â°C, have been studied in the solid state, using both X-ray and ultraviolet photoelectron spectroscopy. The results are analyzed with the help of quantum chemical calculations at the ab initio Hartree-Fock 6-31Gâˆ— level. Based upon the good agreement between theory and experimental, it is determined that clean, oxygen-free, condensed molecular solid films consist of the 2:1 adduct of TMAA, which was previously uncertain. In addition, based upon the electronic structure results, it is clear that the mechanism of the photodecomposition of TMAA can be explained in terms of the wavefunction of electrons photoexcited into the first unoccupied molecular orbital.
28.	Fisher, M., et al. (författare) Collapse of e(-), Na+ pairs into sodium atoms and the reactions of solvated electrons and of e(-), Na+ pairs 1971 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 9:4, s. 309-312 Tidskriftsartikel (refereegranskat)abstract Solvated electrons photoejected from pyrenide, pi(radical anion), may combine in THF with Na+ cations, form e(-), Na+ pairs which can collapse into sodium atoms Na-0. The rate constants of these reactions and those of the various transients with pyrene were determined.
29.	Fisher, M., et al. (författare) Kinetics of electron-transfer B-radical anion + pi -> B + pi(radical anion) and B-radical anion, Na+ + pi -> B + pi(radical anion), Na+ in tetrahydrofuran 1971 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 9:4, s. 306-308 Tidskriftsartikel (refereegranskat)abstract Photoejection of clcctrons from pyrenide. pi(radical anion), in the presence of excess of biphenyl yields biphenylide, B-radical anion, and the rate constants of the reactions B-radical anion + pi -> B + pi(radical anion) and B-radical anion, Na+ + pi -> pi(radical anion), Na+ + B were determined.
30.	Friedlein, Rainer, et al. (författare) High intercalation levels in lithium perylene stoichiometric compounds 2002 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 354:5-6, s. 389-394 Tidskriftsartikel (refereegranskat)abstract Both amorphous and polycrystalline films of the aromatic hydrocarbon perylene are found to accept as high as one lithium per 3.3±0.1 carbon atoms. Phases composed of stoichiometric compounds with two, four and six lithium atoms per molecule are observed. The intercalation involves a substantial charge transfer from the lithium atoms to the molecules. Moreover, a high binding energy of the dopant-induced valence band electronic states is observed by photoelectron spectroscopy. Those observations suggest a high energy storage capacity for small- and medium-size aromatic hydrocarbons and their potential use in batteries. © 2002 Elsevier Science B.V. All rights reserved.
31.	Gador, Niklas, et al. (författare) Coherent multichannel nonadiabatic dynamics and parallel excitation pathways in the blue-violet absorption band of Rb2 2003 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 368:1-2, s. 202-208 Tidskriftsartikel (refereegranskat)
32.	Gelius, Ulrik, et al. (författare) Ab initio MO SCF calculations of ESCA shifts in sulphur-containing molecules 1970 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 4:8, s. 471-475 Tidskriftsartikel (refereegranskat)abstract Ab initio MO SCF calculations in a Gaussian basis for a number of molecules have been performed to study the chemical shift of sulphur 2p-electrons. Estimates of chemical shifts and comparison with experimental shifts are reported. Sulphur 3d-orbitals are shown to be important for the magnitude of the shifts.
33.	Gel'mukhanov, Faris, et al. (författare) Resonant X-ray Raman scattering from dense gases and solutions 2001 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 346:06-maj, s. 437-442 Tidskriftsartikel (refereegranskat)abstract To complement conventional theory of resonant X-ray Raman scattering (RXS) adapted either for rarefied gases or solids, we propose a theory and corresponding analysis for RXS from dense gases and solutions. We show that the dephasing broadening of the spectral lines due to interaction with buffer or solvent particles qualitatively changes the physics of the X-ray scattering. The dephasing results in an additional, two-step (TS) scattering, contribution to the RXS cross-section, which interferes with the Raman one-step (OS) channel and which shows a nondispersive behaviour, This results in a doubling of the spectral lines by detuning the excitation frequency away from resonance. The theory is demonstrated numerically for RXS of formaldehyde in solution.
34.	Goscinski, Osvaldo (författare) Density of states in narrow energy bands 1971 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 9:4, s. 293-295 Tidskriftsartikel (refereegranskat)abstract The density of states in the one-band short-range interaction model approximated with Hubbard's decoupling is equal to the I-independent band theoretical result at E = T-o and E = T-o + E. Improved decoupling procedures remove this anomaly.
35.	Goscinski, Osvaldo, et al. (författare) Dispersion forces, second- and third-order energies 1968 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 2:5, s. 299-302 Tidskriftsartikel (refereegranskat)abstract The properly symmetrized second order energy, epsilon(Q)(2). has been observed to approach one half of the correct dispersion energy epsilon(2) for large interactomic distances. We contend that the proper quantity to be examined is epsilon(Q)(2)lambda(Q). lambda(Q) approaches epsilon(Q)(2)/(epsilon(Q)(2) - epsilon(Q)(3)) approximate to 2 at R=8a(o) for H-2 and epsilon(Q)(2)/epsilon(Q)(3) approximate to 2. Hence E-o - epsilon(Q)(1) + epsilon(Q)(2) is a bad approximation.
36.	Goscinski, Osvaldo, et al. (författare) Moment-conserving decoupling of Green functions via Pade approximants 1970 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 7:6, s. 573-576 Tidskriftsartikel (refereegranskat)abstract A generalization of the Pade approximant technique obtained by inner projections leads to approximate Green functions whose spectral densities satisfy a certain number of frequency moments. This approach contains decoupling schemes previously given and their explicit representation in terms of the moments.
37.	Grage, M.M.-L., et al. (författare) Conformational disorder of a substituted polythiophene in solution revealed by excitation transfer 2001 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 339:1-2, s. 96-102 Tidskriftsartikel (refereegranskat)abstract Anisotropy and isotropic transient absorption decays of a polythiophene derivative in dilute solution have been measured and compared to calculated decays on Monte Carlo simulated polymer chains to obtain knowledge about the geometrical conformation of the polymer. The polymer chain conformations are generated by a partially correlated self-avoiding random walk. Excitation migration along the isolated chain is modeled assuming a hopping mechanism. This approach can be used to determine conformational disorder and possible realizations of the polymer chains in solution as well as the trapping time and migration length of the excitation. © 2001 Elsevier Science B.V.
38.	Granlund, Thomas, et al. (författare) A polythiophene microcavity laser 1998 Ingår i: Chemical Physics Letters. - : Elsevier. - 0009-2614 .- 1873-4448. ; 288:5-6, s. 879-884 Tidskriftsartikel (refereegranskat)abstract We report photopumped lasing in a microcavity device with a polythiophene layer as the emitter. These microcavity devices are built by joining two polymer coated dielectric mirrors at elevated temperature. When photopumping the film, a lasing threshold is observed at 120 nJ/cm(2). Comparative studies with fast pump-probe spectroscopy of thin polythiophene films and the same polymer in photopumped lasing studies, indicate that the gain coefficient is 80 +/- 20 cm(-1), and that the exciton concentration is 2 X 10(17) cm(-3) at the lasing transition, well below the exciton-exciton recombination level. (C) 1998 Elsevier Science B.V. All rights reserved.
39.	Guo, J. D., et al. (författare) Density functional theory study of the canthaxanthin and other carotenoid radical cations 2002 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 366:02-jan, s. 73-81 Tidskriftsartikel (refereegranskat)abstract B3LYP hybrid density functional theory method is employed to study the five carotenoid radical cations of canthaxanthin (1), 7',7'-dimethyl-7'-apo-beta-carotene (2), 8'-apo-beta-carotene-8'-al hydrazone (3), 7',7'-dicyano-7'-apo-beta-carotene (4), and 8'-apo-beta-carotene-8'-al (5). The radicals are characterized by means of their geometries, spin populations, and isotropic hyperfine coupling constants. It is shown that for all the systems, the unpaired spin is delocalized over the whole pi-conjugated system in an odd-alternant pattern. As a result of this, the hyperfine coupling constants are rather low. The radical cations of 1, 2, and 3, have very similar properties to the unsubstituted P-carotene radical, while the dicyano- and aldehyde-substitutions result in significantly different electronic structures.
40.	Hamrin, Kjell, et al. (författare) Ionization energies in methane and ethane measured by means of ESCA 1968 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 1:13, s. 613-615 Tidskriftsartikel (refereegranskat)abstract Ionization energies for the molecular orbitals in methane and ethane are obtained by means of the ESCA technique. In methane the 2a(1) electrons are found at a binding energy of 23.1 eV: in ethane the 2a(1) level is split up in two levels due to the interaction between the carbon atoms.
41.	Hamrin, Kjell, et al. (författare) Structure studies of sulphur compounds by ESCA 1968 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 1:11, s. 557-559 Tidskriftsartikel (refereegranskat)abstract Results, obtained by means of the ESCA-technique (Electron Spectroscopy for Chemical Analysis), are reported on the correlation between the binding energy of the inner electrons of sulphur and the chemical state and environment, with particular emphasis on the sulphur-oxygen bond. A charge-binding energy correlation is established which can be used for the estimation of charge on sulphur in compounds with uncertain structure or composition.
42.	Hermansson, Kersti (författare) A simulated X-ray diffraction study of liquid water : Beyond the spherical-atom approximation 1996 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 260:1-2, s. 229-235 Tidskriftsartikel (refereegranskat)abstract The total electron density of a water molecule differs significantly from the superposition of the O + H + H spherical-atom densities by way of bonding and lone-pair electron charge accumulations. Such non-spherical electron density features on neighbouring molecules typically lie in the range 2-4 Angstrom apart in liquid water. Their influence on the diffracted coherent X-ray intensity for liquid water has been simulated, based on molecular dynamics data and non-spherical atomic electron deformation functions, for the water molecule. It is found that in the liquid water sample, the deformation densities on different molecules interfere significantly in the scattering process, but the effect is largely eliminated because of statistical cancellations over Q vector directions and time, The result is that the influence from the deformation densities on g(r) is large for intramolecular distances, but small for intermolecular distances.
43.	Hermansson, Kersti, et al. (författare) AN ABINITIO STUDY OF ANHARMONIC POTENTIAL-ENERGY SURFACES FOR BOUND WATER-MOLECULES 1988 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 146:5, s. 459-464 Tidskriftsartikel (refereegranskat)
44.	Hermansson, Kersti, et al. (författare) ELECTRON-DENSITY OF H2O IN A CRYSTALLINE ENVIRONMENT 1981 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 80:1, s. 64-68 Tidskriftsartikel (refereegranskat)
45.	Hermansson, Kersti (författare) INFLUENCE OF RIGID-BODY MOTION ON THE DEFORMATION ELECTRON-DENSITY OF H2O 1983 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 99:4, s. 295-300 Tidskriftsartikel (refereegranskat)
46.	HERMANSSON, KERSTI, et al. (författare) NONADDITIVITY OF OH FREQUENCY-SHIFTS IN ION WATER-SYSTEMS 1995 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 233:4, s. 371-375 Tidskriftsartikel (refereegranskat)abstract The intramolecular OH stretching frequency shift observed for water on formation of 'cation-water...H-bond acceptor' complexes is highly non additive. The uncoupled OH frequency shift has been calculated by ab initio methods for q(+)-OH2 and OH2...q(-) complexes of different geometries and for a series of Mg2+.(H2O)(n)...(H2O)(m) complexes, and we argue that the non-additivity (cooperativity) of the frequency shifts is largely a consequence of the parabolic shape of the frequency versus electric field curves.
47.	HERMANSSON, KERSTI (författare) O-H BONDS IN ELECTRIC-FIELDS - ELECTRON-DENSITIES AND VIBRATIONAL FREQUENCY-SHIFTS 1995 Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 233:4, s. 376-382 Tidskriftsartikel (refereegranskat)abstract The changes in the electron density distribution caused by varying the O-H bond length for HDO and OH- in uniform electric fields are investigated and related to the frequency shifts for the uncoupled O-H stretching vibration. Numerical integration of difference density maps, Delta rho=rho(r(OH)+Delta r(OH))-rho(r(OH)), reproduces the electronic contribution to theta mu(parallel to)(total)/theta r(OH), if the integration is carried out to a distance of approximate to 3.5 Angstrom from the O atom. The frequency shift Delta nu, is proportional to -E(parallel to) X[d mu(parallel to)(permanent)(r(OH))/dr(OH)]-1/2E(parallel to)[theta mu(parallel to)(induced)(E(parallel to), r(OH))/theta r(OH)] and electron density maps corresponding to the electronic parts of these terms are presented. Experimentally it has been found that the OH- ion shows a frequency upshift when bound in a moderately strong field, while water molecules show a downshift. The electron density maps show why d mu(parallel to)(permanent)(r(OH))/dr(OH) is positive for HDO and negative for OH-, resulting in a downshift for bound water an an upshift for bound OH-. For positive fields, theta mu(parallel to)(induced)/theta r(OH) is positive for both HDO and OH- and gives a downshift contribution.
48.	Himo, Fahmi (författare) Stability of protein-bound glycyl radical : a density functional theory study 2000 Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 328:3, s. 270-276 Tidskriftsartikel (refereegranskat)abstract Density functional theory is used to study different models of the glycyl radical in proteins. The radical is characterized by means of the C-alpha-H bond strength, geometry, spin distribution, and hyperfine parameters. It is shown that, due to substituent effects from the peptide bond, the protein-bound glycyl radical is less stable than the nonprotein-bound one. This effect is of great importance for the biological function of the glycyl radical. The capto-dative resonance stabilization is confirmed, and new resonances are suggested to arise due to the peptide bond, resulting in further delocalization of the unpaired spin.
49.	Hugosson, Håkan Wilhelm, et al. (författare) Phase stability diagrams of transition metal carbides, a theoretical study 2001 Ingår i: CHEMICAL PHYSICS LETTERS. - 0009-2614 .- 1873-4448. ; 333:6, s. 444-450 Tidskriftsartikel (refereegranskat)abstract The experimental phase diagrams at T=0 of the refractory compounds ZrC, NbC and MoC have been reproduced with great accuracy from first principles theory. The energy of formation for these compounds has been calculated for several phases and stoichiometries in order to understand, for example, the differences and changes in homogeneity ranges found in these systems. This determination of relative phase stabilities for a wide range of concentrations is necessary for first principles determination of phase diagrams for these compounds with complex bonding and structural properties as well as technological importance.
50.	Hugosson, Håkan Wilhelm, 1972-, et al. (författare) Phase stability diagrams of transition metal carbides, a theoretical study 2001 Ingår i: Chemical Physics Letters. - : Elsevier. - 0009-2614 .- 1873-4448. ; 333:6, s. 444-450 Tidskriftsartikel (refereegranskat)abstract The experimental phase diagrams at T=0 of the refractory compounds ZrC, NbC and MoC have been reproduced with great accuracy from first principles theory. The energy of formation for these compounds has been calculated for several phases and stoichiometries in order to understand, for example, the differences and changes in homogeneity ranges found in these systems. This determination of relative phase stabilities for a wide range of concentrations is necessary for first principles determination of phase diagrams for these compounds with complex bonding and structural properties as well as technological importance.

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