Theoretical Electronic Transition Probabilities in Diatomic Molecules II. 13-Electron Sequence

Abstract

Hartree–Fock (HF) electronic dipole‐momentum and dipole‐length transition moments, $\mathrm{M(R)}$ and $\mathrm{M̄(R)}$ , respectively, are presented as a function of the internuclear distance $R$ for the ${\mathrm{N}}_2^{+}{\mathrm{(B}}^2{\Sigma }_u^{+}{\mathrm{\hspace{0.17em}-\hspace{0.17em}X}}^2{\Sigma }_g^{+})$ first negative and ${\mathrm{(A}}^2{\Pi }_u{\mathrm{\hspace{0.17em}-\hspace{0.17em}X}}^2{\Sigma }_{\mathrm{g>}}^{+})$ Meinel systems. They are compared with “experimental” $\mathrm{M(R)}$ and $\mathrm{M̄(R)}$ curves obtained by using relative band transition probability and upper‐state lifetime measurements recently reported in the literature. Vibrational averages of both the theoretical and “experimental” transition moments are computed and used to calculate some relative band oscillator strengths $f_{\mathrm{\upsilon \prime \upsilon ″}}{\mathrm{\hspace{0.17em}/\hspace{0.17em}f}}_{00}$ . The HF $f_{00}$ value of 0.1370 for the first negative system differs from experiment by a factor of 5.6. For the Meinel system the HF $f_{00}$ value of 1.065 × 10⁻² is too large by a factor of 3.3 or 7.3 depending on whether the lifetime data of O'Neil and Davidson or that of Hollstein et al. are used to determine the experimental value. The HF transition‐moment calculations at a single value of $R$ are also reported for the ${\mathrm{(B}}^2{\Sigma }_u^{+}{\mathrm{\hspace{0.17em}-\hspace{0.17em}X}}^2{\Sigma }_g^{+})$ and ${\mathrm{(A}}^2{\Pi }_u{\mathrm{\hspace{0.17em}-\hspace{0.17em}X}}^2{\Sigma }_g^{+})$ systems of C₂⁻ and for the ${(}^2{\Pi }_i{\mathrm{\hspace{0.17em}-\hspace{0.17em}X}}^2{\Sigma }^{+})$ and ${(}^2{\Pi }_r{\mathrm{\hspace{0.17em}-\hspace{0.17em}X}}^2{\Sigma }^{+})$ systems of CN, CO⁺, BO, BF⁺, and BeF. Electronic absorption oscillator strengths are presented and compared with experiment where possible.