The electron–ion dynamics in ionization of lithium carbide molecule under femtosecond laser pulses

• The electron–ion dynamics of Li2C2Li2C2 molecule under femtosecond laser pulses have been studied by TDDFT;
• The on- and off-resonant ionization processes have been induced by regulating laser frequency and intensity;
• The on-resonant processes induce pronounced enhancement in ionization, bond length vibration, and energy absorption;
• The relations between escaped electron number and absorbed photon number are well discussed;
• The effect of self-interaction error from correlation and exchange functional LDA on ionization has been studied.

The electron–ion dynamics of the linear lithium carbide molecule under femtosecond laser pulses have been investigated in the framework of Ehrenfest molecular dynamics, in which valence electrons are treated quantum mechanically by time-dependent density functional theory (TDDFT) and ions are described classically. The on- and off-resonant multiphoton ionization processes have been induced by regulating laser frequency and laser intensity. The laser pulse with on-resonant frequency induces pronounced enhancement in electron ionization, bond length vibration, and energy absorption. Moreover, the coulomb explosion is preferred to occur in the on-resonant case, which is in qualitative agreement with previous theoretical investigations. The subtle relations between escaped electron number and absorbed photon number are well discussed with the increasing of laser intensity. Finally, the effect of self-interaction error is analyzed by comparing escaped electron number calculated with LDA and LDA-ADSIC. And the revTPSS-meta-GGA, a currently more accurate nonempirical exchange–correlation energy functional from a point of static density functional theory, is introduced to display its capability for the description of ionization process within nonlinear and the nonperturbative regime of isolated systems.