Long time simulations, up to 100 ns, have been performed for the fragmentation of Kr clusters after electron impact ionization. They rely on DIM approaches and hybrid non-adiabatic dynamics combining mean field and decoherence driven either by Tully fewest switches (TFS) algorithm or through electronic amplitude (AMP) calculations. With both methods, for the first time, when the initial electronic excited state belongs to group II correlating to P atomic ions, the fragmentation ratio in mainly monomer and dimer ions agrees very well with known experimental results.
View Article and Find Full Text PDFPost-ionization fragmentation of small ionic krypton clusters, Kr (N = 3-13), has been investigated using a semiclassical non-adiabatic dynamics approach consisting of classical treatment of atomic nuclei and full quantum treatment of electrons, and an extended diatomics-in-molecules model including the spin-orbit coupling as well as leading three-body interaction corrections. Electronic quantum decoherence has also been considered via a simplified scheme proposed previously. The positive charge has been initially localized on a randomly selected atom in the form of a localized P positive hole.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2015
Semiclassical methods for non-adiabatic dynamics simulations, based on a semiempirical diatomics-in-molecules model of intracluster interactions and the mean-field dynamical approach with the inclusion of quantum decoherence, have been used to study the photodissociation of argon cluster cations, Ar(N)(+)(N = 6-19), at E(phot) = 2.35 eV. Time periods upto t = 200 ps have been considered and abundance of ionic and neutral fragments, their time evolution and stability have been investigated and compared with available experimental data as well as earlier theoretical studies.
View Article and Find Full Text PDFMomentum-transfer collision cross-sections and integral collision cross-sections for the collision-induced dissociation are calculated for collisions of ionized argon dimers with argon atoms using a nonadiabatic semiclassical method with the electronic Hamiltonian calculated on the fly via a diatomics-in-molecules semiempirical model as well as inverse-method modeling based on simple isotropic rigid-core potential. The collision cross-sections are then used in an optimized Monte Carlo code for evaluations of the Ar 2 (+) mobility in argon gas, longitudinal diffusion coefficient, and collision-induced dissociation rates. A thorough comparison of various theoretical calculations as well as with available experimental data on the Ar 2 (+) mobility and collision cross-sections is performed.
View Article and Find Full Text PDFPhotoabsorption and subsequent photodissociation of two structural isomers of Ar(3) (+) are studied via semiclassical non-adiabatic dynamics simulations. Several experimental observables are simulated under various plausible experimental conditions with the main emphasis on the differences between the data produced for the two isomers. They include photoabsorption cross section, total kinetic energy released, fragments kinetic energy distributions, and distribution of the total kinetic energy among photofragments represented via Dalitz plots.
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