Electron density changes and high harmonics generation in H

Under interaction with a high-intensity laser field, the real-time femtosecond dynamics of the electron density in the H2 molecule has been studied quantum mechanically. For this purpose, a time-dependent generalized nonlinear Schrödinger equation of motion, developed earlier in our laboratory by combining density functional theory and quantum fluid dynamics in real space, is solved numerically at the equilibrium internuclear distance of the molecule. By employing various time-dependent calculated properties as probes, information and insight are obtained about the phenomena of excitation, ionization, bond-softening, dipole formation and high-harmonics generation. The present approach goes beyond the linear response formalism