The impact-parameter method for electron-impact excitation of diatomic molecules is reformulated to explicitly treat molecular vibration and rotation and to permit the study of molecular dissociation. Applications are made to optically allowed transitions involving the X ${}^1$${\Sigma }_g^{+}$, B ${}^1$${\Sigma }_u^{+}$, and B’ ${}^1$${\Sigma }_u^{+}$ states of ${\mathrm{H}}_2$. The resulting cross sections are compared to other theoretical calculations and to experimental data. This method is applicable to heavy diatomic molecules and is expected to be useful in studying trends in electronic excitation and dissociation cross sections associated with variations in internal energy.

• Received 26 December 1984

DOI:https://doi.org/10.1103/PhysRevA.32.3354