Electric-field effects on the hydrogen molecule in the excited state: ${\mathit{B}}^1$${\mathrm{\Sigma }}_{\mathit{u}}^{+}$ of ${\mathrm{H}}_2$

A variational-perturbation method and explicitly correlated wave functions have been used to calculate the frequency-dependent polarizability α(ω,R) for the ${\mathit{B}}^1$ ${\mathrm{\Sigma }}_{\mathit{u}}^{+}$ state of the hydrogen molecule. The polarizability was calculated for the range 0.8${\mathit{a}}_0$≤R≤12.0${\mathit{a}}_0$ and for a wide range of electric-field frequencies ω. The behavior of this property is discussed in terms of the internal structure of the molecule and the electron density. The vibrational and rotational averaging of α(ω,R) was performed. A comparison with earlier Hartree-Fock and configuration-interaction calculations is presented.