133 research outputs found
Anomalous molecular dynamics in the vicinity of conical intersections
Conical intersections between molecular electronic potential surfaces greatly
affect various properties of the molecule. Molecular gauge theory is capable of
explaining many of these often unexpected phenomena deriving from the physics
of the conical intersection. Here we give an example of anomalous dynamics in
the paradigm of the Exe Jahn-Teller model, which does not allow a simple
explenation 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 molecular vibrations. Furthermore, via ab initio calculations the
findings are as well demonstrated to appear in realistic systems such as the
Li3 molecule.Comment: 5 pages, 2 figure
Molecular excitation in the Interstellar Medium: recent advances in collisional, radiative and chemical processes
We review the different excitation processes in the interstellar mediumComment: Accepted in Chem. Re
Recent Advances in Explicitly Correlated Coupled-Cluster Response Theory for Excited States and Optical Properties
Bedarfslagen, BedĂŒrfnisse und sektorenĂŒbergreifende VersorgungsverlĂ€ufe auĂerklinisch beatmeter Intensivpatienten - Ergebnisse qualitativer Interviews
Extrapolating MP2 and CCSD explicitly correlated correlation energies to the complete basis set limit with first and second row correlation consistent basis sets
Accurate extrapolation to the complete basis set (CBS) limit of valence correlation energies calculated with explicitly correlated MP2-F12 and CCSD(T)-F12b methods have been investigated using a Schwenke-style approach for molecules containing both first and second row atoms. Extrapolation coefficients that are optimal for molecular systems containing first row elements differ from those optimized for second row analogs, hence values optimized for a combined set of first and second row systems are also presented. The new coefficients are shown to produce excellent results in both Schwenke-style and equivalent power-law-based two-point CBS extrapolations, with the MP2-F12/cc-pV(D,T)Z-F12 extrapolations producing an average error of just 0.17âmEh with a maximum error of 0.49 for a collection of 23 small molecules. The use of larger basis sets, i.e., cc-pV(T,Q)Z-F12 and aug-cc-pV(Q,5)Z, in extrapolations of the MP2-F12 correlation energy leads to average errors that are smaller than the degree of confidence in the reference data ( ⌠0.1âmEh). The latter were obtained through use of very large basis sets in MP2-F12 calculations on small molecules containing both first and second row elements. CBS limits obtained from optimized coefficients for conventional MP2 are only comparable to the accuracy of the MP2-F12/cc-pV(D,T)Z-F12 extrapolation when the aug-cc-pV(5+d)Z and aug-cc-pV(6+d)Z basis sets are used. The CCSD(T)-F12b correlation energy is extrapolated as two distinct parts: CCSD-F12b and (T). While the CCSD-F12b extrapolations with smaller basis sets are statistically less accurate than those of the MP2-F12 correlation energies, this is presumably due to the slower basis set convergence of the CCSD-F12b method compared to MP2-F12. The use of larger basis sets in the CCSD-F12b extrapolations produces correlation energies with accuracies exceeding the confidence in the reference data (also obtained in large basis set F12 calculations). It is demonstrated that the use of the 3C(D) Ansatz is preferred for MP2-F12 CBS extrapolations. Optimal values of the geminal Slater exponent are presented for the diagonal, fixed amplitude Ansatz in MP2-F12 calculations, and these are also recommended for CCSD-F12b calculations
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