Electron-impact excitation and emission cross sections of the H_2{ \,}\bpxo{} and \dxo{} states and rotational dependence of photodissociation cross sections of the \bpxo{} and \dxo{} continua.

Rotational and vibrational dependence of photodissociation cross sections and oscillator strengths to the continuum levels of the H_2{ \,}\bpxo{} and \dxo{} states have been examined. The electron-impact excitation, dissociation and emission cross sections of the \bpxi{} and \dxi{} band systems have been obtained for the first time over a wide energy range by using calculated continuum oscillator strengths along with previously published discrete transition probabilities and Lyman and Werner bands excitation functions. The present \bpxo{} photodissociation cross section from the Ji = 0 level is in excellent agreement with that obtained by Glass-Maujean (1986 Phys. Rev. A 33 346-50). Photoexcitation from the \xxo{(v_i=0)} state to the \dxo{} continuum is found to be weak. The present calculation shows significant contribution of quasi-resonance, which arises from transitions to the quasi-bound levels above the dissociation limit but stabilized by the centrifugal potential. The quasi-resonance is largely responsible for the significant rotational dependence of the continuum oscillator strength of the \bpxo{}-\xxo{(0)} transition, which, in turn, leads to the noticeable temperature dependence of electron-impact excitation and emission cross sections. \bpxi{} and \dxi{} electron-impact excitation, emission, and dissociation cross sections, important for modelling dayglow and auroral activity in the atmospheres of the outer planets, are presented. [ABSTRACT FROM AUTHOR]