| Abstract: | Hydrogen molecule in a strong ultrashort magnetic field is investigated through a current-density functional theory (CDFT)
and quantum fluid dynamics (QFD) based approach employing current-density dependent vector exchange-correlation potential
and energy density functional derived with a vorticity variable. The numerical computations through the CDFT based approach
are performed for the H2 molecule, starting initially from its field-free ground state, in a parallel internuclear axis and magnetic field-axis configuration
with the internuclear separation R ranging from 0.1 a.u. to 14.0 a.u., and the strength of the time-dependent (TD) magnetic field varying between 0−1011 G over a few femtoseconds. The numerical results are compared with that obtained using an approach based on the current-density
independent approximation under similar computational constraints but employing only scalar exchange-correlation potential
dependent on the electronic charge-density alone. The current-density based approach yields exchange- and correlation energy
as well as electronic charge-density of the H2 molecule drastically different from that obtained using current-independent approach, in particular, at TD magnetic field-strengths
>109 G during a typical time-period of the field when the magnetic-field had attained maximum applied field-strength and is switched
to a decreasing ramp function. This nonadiabatic behavior of the TD electronic charge-density is traced to the TD vorticity-dependent
vector exchange-correlation potential of the CDFT based approach. The interesting electron dynamics of the H2 molecule in strong TD magnetic field is further elucidated by treating electronic charge-density as an ‘electron-fluid’.
The present work also reveals interesting real-time dynamics on the attosecond time-scale in the electronic charge-density
distribution of the hydrogen molecule. |
