Self-interaction-free TDDFT for nonperturbative treatment of multiphoton processes of heteronuclear diatomic molecular systems in intense laser fields

We present a \textit{self-interaction-free }time-dependent density-functional theory (TDDFT) with proper asymptotic \textit{long-range} potential for nonperturbative treatment of multiphoton processes of many-electron heteronuclear molecular systems in intense laser fields. A \textit{time-dependent} \textit{generalized pseudospectral} method is developed with the use of a new mass-weighted prolate spheroidal coordinate system for accurate solution of the electronic structure and TDDFT equations for two-center heteronuclear diatomic systems. The procedure allows \textit{nonuniform} and optimal spatial grid discretization of the Hamiltonian in the adapted prolate spheroidal coordinates and a split operator scheme in \textit{energy} representation is used for the time propagation of individual molecular spin orbital's in space and time. The theory is applied to a detailed \textit{all-electron} study of high-order harmonic generation (HHG) and multiphoton ionization processes of CO in intense laser fields. Both even and odd-order harmonics are predicted for the CO molecule.