Abstract
We present an implementation of a time-dependent multiconfiguration self-consistent-field (TD-MCSCF) method [R. Anzaki et al., Phys. Chem. Chem. Phys. 19, 22008 (2017)] with the full configuration interaction expansion for coupled electron-nuclear dynamics in diatomic molecules subject to a strong laser field. In this method, the total wave function is expressed as a superposition of different configurations constructed from time-dependent electronic Slater determinants and time-dependent orthonormal nuclear basis functions. The primitive basis functions of nuclei and electrons are strictly independent of each other without invoking the Born-Oppenheimer approximation. Our implementation treats the electronic motion in its full dimensionality on curvilinear coordinates, while the nuclear wave function is propagated on a one-dimensional stretching coordinate with rotational nuclear motion neglected. We apply the present implementation to high-harmonic generation and dissociative ionization of a hydrogen molecule and discuss the role of electron-nuclear correlation.
Highlights
The rapid development of laser technology enables the generation of coherent light sources that cover a broad frequency range, from the midinfrared to the x-ray regime [1–5]
As a first numerical test, we have applied this method to the ground state as well as the laser-driven dynamics of the H2 molecule
For laser-driven dynamics, we have shown that the method can systematically improve the accuracy for describing the highly nonlinear highharmonic generation (HHG) phenomenon by increasing the number of electronic and nuclear orbital functions
Summary
The rapid development of laser technology enables the generation of coherent light sources that cover a broad frequency range, from the midinfrared to the x-ray regime [1–5]. In the full-CI case, the computational cost due to CI coefficients is proportional to the number of electron distributions among all spin orbitals, which increases factorially with the number of electrons, hindering its application beyond small molecular systems To subjugate this difficulty, variants that go beyond the restriction to the full-CI expansion are under active development, which we refer to as time-dependent multiconfiguration self-consistent-field (TD-MCSCF) methods [22,23] in the general case. Kato and Yamanouchi developed an extended MCTDHF method [35] by using a basis of Slater determinants with time-dependent nuclear orbitals for the fermionic protons while keeping heavy nuclei fixed This method has been applied to calculate the ground-state properties of a model one-dimensional hydrogen molecule [36], which shows good agreement with the direct solution of the time-dependent Schrödinger equation (TDSE).
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call