Time-dependent rovibronic wave function of H 2 + by multiconfiguration theory

Abstract

We simulate the time-dependent rovibronic wave function of H2 + in an intense, few-cycle 400 nm laser field using a time-dependent multiconfiguration method. 
By calculating the expectation value of the total angular momentum squared, the time-dependent expectation value of the internuclear distance, the induced dipole moment, and the probability of electron ejection, we show that rotational, vibrational and electronic excitation as well as ionization can be simulated. 
We compare the results obtained using the time-dependent multiconfiguration method with results obtained using the standard two-state Born-Oppenheimer approximation and a close-coupling expansion. We find that the multiconfiguration results for a wave function constructed using 21 time-dependent orbitals are in good agreement with the close-coupling results, 
but that the two-state Born-Oppenheimer approximation leads to an underestimation of the induced dipole moment by a factor of two and an overestimation the expectation value of the total angular momentum squared by a factor of 2.3.