Ab initio relativistic treatment of the intercombination $a^3\Pi -X^1{\Sigma }^{+}$ Cameron system of the CO molecule

Abstract

The intercombination $a^3\Pi -X^1{\Sigma }^{+}$ Cameron system of carbon monoxide has been computationally studied in the framework of multi-reference Fock space coupled cluster method with the use of generalized relativistic pseudopotential model for the effective introducing the relativity in all-electron correlation treatment. The extremely weak $a^3{\Pi }_{\Omega =0^{+},1}-X^1{\Sigma }^{+}$ transition probabilities and radiative lifetimes of the metastable $a^3\Pi$ state were calculated and compared with their previous theoretical and experimental counterparts. The impact of a presumable variation of the fine structure constant $\alpha =e^2/\hslash c$ on transition strength of the Cameron system has been numerically evaluated as well.

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