A Theoretical Study of Electronic Dynamics and Deformation of CO₂ in Intense Laser Fields

Abstract

Deformations of CO 2 , CO 2 + , and CO 2 2+ in intense laser fields (>10 14 W/cm 2 ) are investigated by using potential energy surfaces of field-following adiabatic states at various instantaneous field strengths. The adiabatic states are obtained by ab initio molecular orbital calculations. To predict tunnel ionization of multi-electron molecules, we propose a new approach based on the idea that electron transfer induced by an intense laser field charges each atom in a molecule and that ionization proceeds via the most negatively (or least positively) charged atomic site. We conclude that bond stretching in CO 2 2+ accompanied by large amplitude bending motion is responsible for the experimentally determined geometrical structure of Coulomb explosion species CO 2 3+ , namely, that the C-O bond length is stretched to about 1.6 Å and the mean amplitude of bending is relatively large (∼40°). † Part of the special issue "Edward W. Schlag Festschrift".

High-order-harmonic generation from field-distorted orbitals

“…We obtain initial and final states by calculating field-dependent orbitals with quantum chemistry methods [34] using an aug-cc-pTZV basis set [35,36]. This approach was successfully used to study deformations in CO 2 molecules subject to even stronger fields than used here [37]. To obtain the spectrum, the field-distorted orbitals and corresponding energies are calculated at every time step needed for an accurate evaluation of the integral in Eq.…”

Theoretical Investigations of the Electronic and Nuclear Dynamics of Molecules in Intense Laser Fields: Quantum Mechanical Wave Packet Approaches

“…This approach has an advantage that the properties of the adiabatic states of polyatomic molecules can be evaluated by ab initio molecular orbital (MO) methods intended to calculate bound electronic states. 47,48 The structure of this paper is as follows. Section 2 is used to explain basic concepts such as tunnel ionization.…”

“…However, the dynamical behaviors of nuclei for the three states will be nearly alike, because the potential surfaces of the lowest three adiabatic states have nearly the same shape over a wide range of field strengths. 47 …”

Изменение Нормальных Координат И Геометрических Параметров Молекулы В Лазерном Поле

“…Изменение геометрических параметров в многоатом-ных молекулах наблюдалось при изучении кулоновского взрыва (см., например, [32][33][34][35][36][37][38][39][40]). Такое изменение со-провождается в общем случае изменением нормальных координат, определяющих положения ядер атомов, вхо-дящих в состав молекулы.…”

“…Отметим, что взаимодействие лазерного излуче-ния с пространственно-ориентированными молекулами исследуется экспериментально во многих работах (см., например, [28][29][30][31]). Изменение геометрических параметров в многоатом-ных молекулах наблюдалось при изучении кулоновского взрыва (см., например, [32][33][34][35][36][37][38][39][40]). Такое изменение со-провождается в общем случае изменением нормальных координат, определяющих положения ядер атомов, вхо-дящих в состав молекулы.…”