| 1. |
- Ghassemi, Elham Nour, et al.
(författare)
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A diabatic representation of the two lowest electronic states of Li-3
- 2014
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 140:15, s. 154304-
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Tidskriftsartikel (refereegranskat)abstract
- Using the Multi-Reference Configuration Interaction method, the adiabatic potential energy surfaces of Li-3 are computed. The two lowest electronic states are bound and exhibit a conical intersection. By fitting the calculated potential energy surfaces to the cubic E circle times epsilon Jahn-Teller model we extract the effective Jahn-Teller parameters corresponding to Li-3. These are used to set up the transformationmatrix which transforms from the adiabatic to a diabatic representation. This diabatization method gives a Hamiltonian for Li-3 which is free from singular non-adiabatic couplings and should be accurate for large internuclear distances, and it thereby allows for bound dynamics in the vicinity of the conical intersection to be explored.
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| 2. |
- Larson, Jonas, et al.
(författare)
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Anomalous molecular dynamics in the vicinity of a conical intersection
- 2013
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Ingår i: Europhysics letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 101:4
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Tidskriftsartikel (refereegranskat)abstract
- Conical intersections between molecular electronic potential energy surfaces can greatly affect molecular dynamics and chemical properties. Molecular gauge theory is capable of explaining many of these often unexpected phenomena deriving from the physics of the conical intersection. Here we will give an example of anomalous dynamics in the paradigm E x epsilon Jahn-Teller model, which does not allow for a simple explanation in terms of standard molecular gauge theory. By introducing a dual gauge theory, we unwind this surprising behavior by identifying it with an intrinsic spin Hall effect. Thus, this work link knowledge of condensed-matter theories with non-adiabatic molecular dynamics. Furthermore, via ab initio calculations of potential energy surfaces, the findings are as well demonstrated to appear in a realistic system such as the Li-3 molecule.
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| 3. |
- Wang, Dong, et al.
(författare)
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Quantum interference structures in trapped ion dynamics beyond the Lamb-Dicke and rotating wave approximations
- 2008
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 77:5
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Tidskriftsartikel (refereegranskat)abstract
- We apply wave-packet methods to study an ion-trap system imposing neither the rotating wave nor the Lamb-Dicke approximations. By this approach we show the existence of states with restricted phase-space evolution as a genuine consequence of quantum interference between wave-packet fractions. A particular instance of such a state oscillates between maximal entanglement and pure disentanglement between the constitute subsystems, where the characteristic crossover time is very rapid. Over longer time periods the dynamics of these states exhibits collapse-revival patterns with well-resolved fractional revivals in autocorrelation, inversion, and entanglement.
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| 4. |
- Anderson, Emma K., 1986-, et al.
(författare)
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Fragmentation of and electron detachment from hot copper and silver dimer anions : A comparison
- 2023
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - 2469-9926 .- 2469-9934. ; 107:6
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Tidskriftsartikel (refereegranskat)abstract
- We measured the spontaneous decays of internally hot copper and silver dimer anions, and , stored in one of the two ion-beam storage rings of the Double Electrostatic Ion Ring Experiment (DESIREE) at Stockholm University. A coincidence detection technique was utilized enabling essentially background-free measurements of -> Cu + Cu- and -> Ag + Ag- fragmentation rates. Furthermore, the total rates of neutral decay products (monomers and dimers) were measured and the relative contributions of fragmentation and electron emission ( -> Cu2 + e- and -> Ag2 + e-) were deduced as functions of storage time. Fragmentation is completely dominant at early times. However, after about 20 ms of storage, electron emission is observed and becomes the leading decay path after 100 ms for both dimer anions. The branching ratios between fragmentation and electron emission (vibrationally assisted autodetachment processes) are very nearly the same for and Ag-2 throughout the present storage cycle of 10 seconds. This is surprising considering the difference between the electron affinities of the neutral dimers, Cu2 and Ag2, and the difference between the and the dissociation energies.
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| 5. |
- Anderson, Emma K., et al.
(författare)
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Spontaneous electron emission from hot silver dimer anions: Breakdown of the Born-Oppenheimer approximation
- 2020
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 124
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Tidskriftsartikel (refereegranskat)abstract
- We report the first experimental evidence of spontaneous electron emission from a homonuclear dimer anion through direct measurements of Ag−2 → Ag2 + e− decays on milliseconds and seconds timescales. This observation is very surprising as there is no avoided crossing between adiabatic energy curves to mediate such a process. The process is weak, yet dominates the decay signal after 100 ms when ensembles of internally hot Ag−2 ions are stored in the cryogenic ion-beam storage ring, DESIREE, for 10 s. The electron emission process is associated with an instantaneous, very large reduction of the vibrational energy of the dimer system. This represents a dramatic deviation from a Born-Oppenheimer description of dimer dynamics.
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| 6. |
- Andersson, Egil, et al.
(författare)
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Single-photon core-valence double ionization of molecular oxygen
- 2008
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 78, s. 023409-
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Tidskriftsartikel (refereegranskat)abstract
- Single-photon core-valence double ionization of molecular oxygen has been studied using a magnetic bottle time-of-flight electron coincidence spectrometer. The K-1V-1 double ionization electron spectrum of O-2 is reported and is assigned with the aid of ab initio calculations. A direct comparison of the core-valence double ionization electron spectra with the conventional valence band photoelectron spectrum is made. The lowest core-valence double ionization energy is found to be 571.6 eV and is associated with a (3)Pi dicationic state.
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| 7. |
- Arking, D. E., et al.
(författare)
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Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization
- 2014
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Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 46:8, s. 826-836
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Tidskriftsartikel (refereegranskat)abstract
- The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∼ 8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD. © 2014 Nature America, Inc.
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| 8. |
- Brinne Roos, Johanna, et al.
(författare)
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A direct, local model of dissociative recombination of HF
- 2009
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 192
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Tidskriftsartikel (refereegranskat)abstract
- The direct mechanism of dissociative recombination of HF+ have been studied by propagating wave packets on 30 resonant states. The relevant electronic states have been calculated ab initio with electron scattering calculations and multireference configuration interaction calculations. We obtain a qualitative good agreement with experiments for energies in the range from 0.04 eV to 10 eV. Some of the structures in the experimental cross section can be explained by the direct capture and dissociation along the resonant states. To fully describe the measured cross section, the electronic couplings between the neutral states cannot be neglected.
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| 9. |
- Brinne Roos, Johanna, 1976-, et al.
(författare)
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Dissociative recombination of BeH
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The cross section for dissociative recombination of BeH+ is calculated by solution of the timedependent Schrödinger equation in the local complex potential approximation. The effects of couplings between resonant states and the Rydberg states converging to the ground state of the ionare studied. The relevant potentials, couplings and autoionization widths are extracted using abinitio electron scattering and structure calculations, followed by a diabatization procedure. Thecalculated cross sections shows a sizable magnitude at low energy, followed by a high-energy peakcentered around 1 eV. The electronic couplings between the neutral states induce oscillations in thecross section. Analytical forms for the cross sections at low collision energies are given.
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| 10. |
- Brinne Roos, Johanna, 1976-, et al.
(författare)
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Dissociative recombination of HF
- 2008
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : The American Physical Society. - 1050-2947 .- 1094-1622. ; 78:2, s. 022508-1-022508-12
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Tidskriftsartikel (refereegranskat)abstract
- The direct mechanism of dissociative recombination of HF+ is studied usingboth time-dependent and time-independent methods, where the dynamics on 30resonant states is explored. The relevant electronic states are calculatedab initio by combining electron scattering calculations with multireference configurationinteraction structure calculations. For collision energies between 0.04 and 10 eV,we obtain qualitative agreement with experiment. At 1.9 eV there isa sharp threshold in both the experimental and theoretical crosssections that can be explained by the opening of newasymptotic limits. The measured cross section below 0.04 eV is notreproduced due to the neglect of the electronic couplings betweenthe neutral states. We examine the validity of the localapproximation for treating autoionization from the resonant states included inthis study.
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