Ab initio studies on the oscillator strength of the spin-forbidden transition in Cl2

Abstract

A relatively strong absorption corresponding to the spin-forbidden transition [Formula: see text] of Cl2 had been observed earlier. Ab initio spin-orbit studies at the ground state equilibrium distance were performed, allowing for the coupling of all excited states up to 90 000 cm−1.It was found that only 21Πu couples with 23Πu to any significant extent. The oscillator strength for [Formula: see text] is calculated to be 0.0084, a factor of 8.3 smaller than the oscillator strength for [Formula: see text].