| 1. |
- Andersson, Egil, et al.
(author)
-
Single-photon core-valence double ionization of molecular oxygen
- 2008
-
In: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 78, s. 023409-
-
Journal article (peer-reviewed)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.
|
|
| 2. |
- Aquilante, Francesco, et al.
(author)
-
Molcas 8 : New capabilities for multiconfigurational quantum chemical calculations across the periodic table
- 2016
-
In: Journal of Computational Chemistry. - : Wiley. - 0192-8651 .- 1096-987X. ; 37:5, s. 506-541
-
Journal article (peer-reviewed)abstract
- In this report, we summarize and describe the recent unique updates and additions to the Molcas quantum chemistry program suite as contained in release version 8. These updates include natural and spin orbitals for studies of magnetic properties, local and linear scaling methods for the Douglas-Kroll-Hess transformation, the generalized active space concept in MCSCF methods, a combination of multiconfigurational wave functions with density functional theory in the MC-PDFT method, additional methods for computation of magnetic properties, methods for diabatization, analytical gradients of state average complete active space SCF in association with density fitting, methods for constrained fragment optimization, large-scale parallel multireference configuration interaction including analytic gradients via the interface to the Columbus package, and approximations of the CASPT2 method to be used for computations of large systems. In addition, the report includes the description of a computational machinery for nonlinear optical spectroscopy through an interface to the QM/MM package Cobramm. Further, a module to run molecular dynamics simulations is added, two surface hopping algorithms are included to enable nonadiabatic calculations, and the DQ method for diabatization is added. Finally, we report on the subject of improvements with respects to alternative file options and parallelization.
|
|
| 3. |
- Bengtson, Charlotta, et al.
(author)
-
Quantum nonlocality in the excitation energy transfer in the Fenna-Matthews-Olson complex
- 2016
-
In: International Journal of Quantum Chemistry. - : Wiley. - 0020-7608 .- 1097-461X. ; 116, s. 1763-1771
-
Journal article (peer-reviewed)abstract
- The Fenna-Matthews-Olson (FMO) complex - a pigment protein complex involved in photosynthesis in green sulfur bacteria - is remarkably efficient in transferring excitation energy from light harvesting antenna molecules to a reaction center. Recent experimental and theoretical studies suggest that quantum coherence and entanglement may play a role in this excitation energy transfer (EET). We examine whether bipartite quantum nonlocality, a property that expresses a stronger-than-entanglement form of correlation, exists between different pairs of chromophores in the FMO complex when modeling the EET by the hierarchically coupled equations of motion method. We compare the results for nonlocality with the amount of bipartite entanglement in the system. In particular, we analyze in what way these correlation properties are affected by different initial conditions. It is found that bipartite nonlocality only exists when the initial conditions are chosen in an unphysiological manner and probably is absent when considering the EET in the FMO complex in its natural habitat. It is also seen that nonlocality and entanglement behave quite differently in this system. In particular, for localized initial states, nonlocality only exists on a very short time scale and then drops to zero in an abrupt manner. As already known from previous studies, quantum entanglement between chromophore pairs on the other hand is oscillating and exponentially decaying and follow thereby a pattern more similar to the chromophore population dynamics. The abrupt disappearance of nonlocality in the presence of nonvanishing entanglement is a phenomenon we call nonlocality sudden death; a striking manifestation of the difference between these two types of correlations in quantum systems.
|
|
| 4. |
- Elander, Nils, et al.
(author)
-
Quantum Scattering with the Driven Schrödinger Approachand Complex Scaling
- 2009
-
In: Few-body systems. - Heidelberg : Springer Verlag. - 0177-7963 .- 1432-5411. ; 45:2-4, s. 197-201
-
Journal article (peer-reviewed)abstract
- Quantum scattering calculations of two and three-body systems with Coulomb interaction using thedriven Schrödinger equation combined with exterior complex scaling are discussed. A rigorous formulationfor two-body scattering is reported, and its generalization to three-body scattering is considered.
|
|
| 5. |
|
|
| 6. |
- Larson, Åsa, et al.
(author)
-
Ion-pair formation in electron recombination with molecular ions
- 2007
-
In: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 88, s. 012065-1-012065-8, s. 012065-
-
Journal article (peer-reviewed)abstract
- By studying ion-pair formation in electron recombination with molecular ions,fundamental knowledge on the molecular dynamics can be obtained. In order to study thesetypes of reactions, both the electron recombination as well as the dynamics all the way to theasymptotic limits must be well described. We have used the wave packet technique to studyion-pair formation in electron recombination with HeH+, HD+, H3+ and HF+. We here discusswhat will determine the general shape of the ion-pair cross section, the threshold effects, possibleinterference effects as well as the ratio of the cross sections of ion-pair formation to dissociativerecombination.
|
|
| 7. |
|
|
| 8. |
- Linusson, Per, et al.
(author)
-
Double photoionization of alcohol molecules
- 2009
-
In: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 80:3, s. 32516-
-
Journal article (peer-reviewed)abstract
- The double valence photoionization spectra of methanol, ethanol, and n-propyl alcohol have been recorded using a time-of-flight photoelectron-photoelectron coincidence technique. The spectra show a well-defined onset followed by broad rounded bands. The lowest vertical double ionization energies have been determined for all molecules and are found to be 32.1, 29.6, and 28.2 eV, respectively. These energies have been applied along with single ionization energies from conventional photoelectron spectra to investigate a recently derived rule of thumb for determination of the lowest double ionization energy in molecules. Many-electron ab initio calculations have been performed on the dicationic ground states in good agreement with the experimental values. For methanol, also excited dicationic states have been calculated up to about 40 eV and used for a detailed interpretation of the experimental spectrum.
|
|
| 9. |
- Mezei, Zsolt, et al.
(author)
-
Double charge transfer in low-energy H+ + H- collisions
- 2010
-
In: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 82:1, s. 14701-
-
Journal article (peer-reviewed)abstract
- The cross section for double charge transfer between H+ and H- at low collision energies (E <= 90 eV) is calculated using a many-state molecular close-coupling model. The wave function is expanded in a diabatic representation of the seven lowest (1)Sigma(+)(g) and the six lowest (1)Sigma(+)(u) states of the hydrogen molecule. The calculated cross section shows clear oscillations as a function of the collision energy, similar to those observed experimentally. However, the magnitude of the calculated cross section is larger than found in experiments. Also, the cross section for double charge transfer in collisions between D+ and H- is calculated.
|
|
| 10. |
- Stenrup, Michael, et al.
(author)
-
A computational study of radiationless deactivation mechanisms of furan
- 2011
-
In: Chemical Physics. - : Elsevier BV. - 0301-0104 .- 1873-4421. ; 379:1-3, s. 6-12
-
Journal article (peer-reviewed)abstract
- Possible mechanisms for the radiationless deactivation of photo-excited furan have been investigated using high-level electronic structure methods. Two different conical intersections between the S0 and S1 electronic states have been characterized, both involving various degrees of CO bond cleavage. One of these corresponds to a planar ring-opened structure and the other to an asymmetric ring-puckered structure. Calculations have been performed in order to establish the vertical electronic spectrum and to investigate the behaviour of the potential energy surfaces as the intersections are approached. The present results indicate that both crossings can be accessed through exothermic and barrierless processes after vertical excitation into the optically bright S2(ππ∗) state. These features make them good candidates to account for efficient radiationless deactivation in furan. The deactivation pathways considered in the present work are close analogues of those previously described for other five-membered heterocycles.
|
|
