| 1. |
- Abe, Minori, et al.
(författare)
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Accurate determination of the enhancement factor X for the nuclear Schiff moment in (TlF)-Tl-205 molecule based on the four-component relativistic coupled-cluster theory
- 2020
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Ingår i: Molecular Physics. - : Taylor & Francis. - 0026-8976 .- 1362-3028. ; 118:23
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Tidskriftsartikel (refereegranskat)abstract
- Studies of parity (P) and time-reversal (T) symmetry violations using molecules are important and attractive because they are complementary to the high-energy tests of physics beyond the Standard Model of elementary particles. The focus of our present work is to surpass the current accuracies of the quantity X, an enhancement factor for the nuclear Schiff moment (Q), and the nucleon electric dipole moments for the (TlF)-Tl-205 molecule. We obtain X = 6856 a.u. using a relativistic coupled-cluster singles and doubles and perturbative triples (CCSD(T)) approach. This new value of X improves the upper limits for Q and the proton EDM by about ten percent over the previous ones. [GRAPHICS] .
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| 2. |
- Afzelius, Mikael, et al.
(författare)
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Exact treatment of classical trajectories governed by an isotropic potential for linewidth computations
- 2004
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Ingår i: Molecular Physics. - : Informa UK Limited. - 1362-3028 .- 0026-8976. ; 102:16-17, s. 1759-1765
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Tidskriftsartikel (refereegranskat)abstract
- Two models for exact classical trajectories in the field of an isotropic potential are investigated for the purpose of semiclassical linebroadening calculations. The first directly uses the exact solution of the classical equation of motion. The second starts from the equation of motion and computes the trajectory by numerical solution of the differential equations. In the framework of both models, all the computations are performed numerically, thus allowing the use of refined ab initio potential energy surfaces. For the example of the linebroadening of pure nitrogen and carbon monoxide, it is shown that, owing to the dominant short-range forces in these self-perturbed molecular systems, the limiting case corresponding to traditional parabolic trajectories can be used without any important loss of precision.
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| 3. |
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| 4. |
- Ai, Yue-Jie, et al.
(författare)
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Role of non-Condon vibronic coupling and conformation change on two-photon absorption spectra of green fluorescent protein
- 2013
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Ingår i: Molecular Physics. - : Informa UK Limited. - 0026-8976 .- 1362-3028. ; 111:9-11, s. 1316-1321
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Tidskriftsartikel (refereegranskat)abstract
- Two-photon absorption spectra of green fluorescent proteins (GFPs) often show a blue-shift band compared to their conventional one-photon absorption spectra, which is an intriguing feature that has not been well understood. We present here a systematic study on one- and two-photon spectra of GFP chromophore by means of the density functional response theory and complete active space self-consistent field (CASSCF) methods. It shows that the popular density functional fails to provide correct vibrational progression for the spectra. The non-Condon vibronic coupling, through the localised intrinsic vibrational modes of the chromophore, is responsible for the blue-shift in the TPA spectra. The cis to trans isomerisation can be identified in high-resolution TPA spectra. Our calculations demonstrate that the high level ab initio multiconfigurational CASSCF method, rather than the conventional density functional theory is required for investigating the essential excited-state properties of the GFP chromophore.
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| 5. |
- Aldongarov, Anuar, et al.
(författare)
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Theoretical study on passivation of small CdS clusters
- 2014
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Ingår i: Molecular Physics. - : Taylor & Francis. - 0026-8976 .- 1362-3028. ; 112:5-6, s. 674-682
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Tidskriftsartikel (refereegranskat)abstract
- We use density functional theory quantum chemical calculations to model optical properties of small cadmium sulphide clusters in order to explore the formation of trap states and the possibility to achieve surface passivation. The addition of capping oxygen ions on the surface of the CdS quantum dots is found to passivate the single-bonded Cd atoms. Added Cu ions resulted in the formation of deep trap states for certain locations of the copper impurity, while removal of single-bonded Cd atoms by adding S or SH groups leads to a band gap increase.
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| 6. |
- Amann-Winkel, Katrin, et al.
(författare)
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Structural differences between unannealed and expanded high-density amorphous ice based on isotope substitution neutron diffraction
- 2019
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Ingår i: Molecular Physics. - : Informa UK Limited. - 0026-8976 .- 1362-3028. ; 117:22, s. 3207-3216
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Tidskriftsartikel (refereegranskat)abstract
- We here report isotope substitution neutron diffraction experiments on two variants of high-density amorphous ice (HDA): its unannealed form prepared via pressure-induced amorphization of hexagonal ice at 77 K, and its expanded form prepared via decompression of very-high density amorphous ice at 140 K. The latter is about 17 K more stable thermally, so that it can be heated beyond its glass-to-liquid transition to the ultraviscous liquid form at ambient pressure. The structural origin for this large thermal difference and the possibility to reach the deeply supercooled liquid state has not yet been understood. Here we reveal that the origin for this difference is found in the intermediate range structure, beyond about 3.6 angstrom. The hydration shell markedly differs at about 6 angstrom. The local order, by contrast, including the first as well as the interstitial space between first and second shell is very similar for both. 'eHDA' that is decompressed to 0.20 GPa instead of 0.07 GPa is here revealed to be rather far away from well-relaxed eHDA. Instead it turns out to be roughly halfway between VHDA and eHDA - stressing the importance for decompressing VHDA to at least 0.10 GPa to make an eHDA sample of good quality.
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| 7. |
- Andersson, Ove, et al.
(författare)
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Chirality and the thermophysical properties of molecular solid phases under pressure: (+)- and (±)-camphor
- 1990
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Ingår i: Molecular Physics. - : Taylor & Francis Group. - 0026-8976 .- 1362-3028. ; 70:6, s. 1065-1083
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Tidskriftsartikel (refereegranskat)abstract
- Thermal conductivity λ, heat capacity per unit volume pcP and P-T phase diagrams are investigated for both (+)- and (±)-camphor. The transient hotwire method is used at temperatures in the range 100–430 K and at pressures up to 1·75 GPa. We detect solid phases I-IV for (+)-camphor and I′-V′ for (±)-camphor. We conclude that λ is independent of enantiomeric composition for plastic-crystal phase pairs I-I′, II-II′ and IV-IV′. Phase V′ also appears to be a plastic-crystal phase. Non-plastic phases III and III′ show a variation of λ with T that differ considerably from that expected for a simple crystal, with the greatest such difference being observed for the racemic compound III′. An unannealed specimen of the racemic compound III′ is probably chirally disordered and shows a variation of λ with T for T < 130 K, which may indicate phonon-assisted fracton hopping.
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| 8. |
- Andersson, Ove, et al.
(författare)
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Thermal conductivity, heat capacity and phase diagram of cyclooctanol in liquid, solid and glassy crystal states under high pressure
- 1990
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Ingår i: Molecular Physics. - : Taylor & Francis Group. - 0026-8976 .- 1362-3028. ; 71:3, s. 523-539
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Tidskriftsartikel (refereegranskat)abstract
- Using the transient hot-wire method, thermal conductivity and heat capacity per unit volume are measured for solid and liquid phases and glassy crystal states of cyclooctanol, and information is provided on the phase diagram under high pressure. A new solid phase (III) is detected and characterized as a normal crystal phase, whereas all other solid phases (I, II, IV, V) are characterized as plastic crystal phases. We find evidence that the plastic crystal phases I, II and IV could each be the source for a distinct glassy crystal state. It is argued for phase II that its possession of both a low thermal conductivity and a low dielectric permittivity could be accounted for by assuming restricted reorientational motion of the molecules. The unusual (although small) decrease of thermal conductivity observed through the glassy to plastic crystal transitions may indicate that phonons can couple to reorientational motion in the plastic crystal phases I, II and IV.
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| 9. |
- Andersson, Ove, et al.
(författare)
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Thermal conductivity of (+)- and (±)-camphor at pressures up to 0·5 GPa and temperatures down to 40 K
- 1992
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Ingår i: Molecular Physics. - : Taylor & Francis. - 0026-8976 .- 1362-3028. ; 76:2, s. 433-444
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Tidskriftsartikel (refereegranskat)abstract
- The transient hot-wire method was used to investigate the thermal conductivity of (+)- and (±)-camphor in the temperature range 40–300 K and for pressures up to 0·5 GPa. Results for the thermal conductivity of crystalline (+)- and (±)-camphor exhibited maximum values at temperatures of 60 and 70 K, respectively, independent of pressure. Above the maxima, the thermal conductivity λ exhibited a less pronounced temperature dependence than the variation λ ∼T-1 which is predicted theoretically for perfect crystals. We showed that the Debye theory can describe the thermal conductivity of molecular crystals like (+)- and (±)-camphor when structural disorder is assumed to provide a significant contribution to the phonon scattering process. We investigated two samples of (±)-camphor of estimated purity 99·3% and 97% and both samples exhibited the same thermal conductivity within experimental inaccuracy.
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| 10. |
- Andersson, Ove, et al.
(författare)
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Thermal conductivity of crystalline and glassy crystal cyclohexanol under pressure
- 1989
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Ingår i: Molecular Physics. - : Taylor & Francis Group. - 0026-8976 .- 1362-3028. ; 66:3, s. 619-635
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Tidskriftsartikel (refereegranskat)abstract
- The thermal conductivity λ of phases liquid, I, II, III and the glassy crystal state of cyclohexanol has been measured using the transient hot-wire method at temperatures in the range 100–370K and at pressures up to 0·7 GPa. It was inferred from the observed temperature dependence of the thermal resistivity W (= λ-1) that molecular orientational disorder made a dominant contribution to the resistivity for the glassy crystal state under isobaric conditions. The same was found for plastic crystal phase I under isochoric conditions and also under isobaric conditions especially at the highest pressure. It was suggested that conformational disorder may make an important contribution to W for molecular crystal phases II and III.
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