Einstein A Coefficients and Oscillator Strengths for the A 2Π-X2Σ+ (Red) and B 2Σ+-X2Σ+ (Violet) Systems and Rovibrational Transitions in the X2Σ+ State of CN

Line strengths have been calculated in the form of Einstein A coefficients and f-values for a large number of bands of the A2Π–X2Σ+ and B2Σ+–X2Σ+ systems and rovibrational transitions within the X2Σ+ state of CN using Western’s pgopher program. The J dependence of the transition dipole moment matrix elements (the Herman–Wallis effect) has been taken into account. Rydberg–Klein–Rees potential energy functions for the A2Π, BΣ, and X2Σ+ states were computed using spectroscopic constants from the A2Π–X2Σ+ and B2Σ+–X2Σ+ transitions. New electronic transition dipole moment functions for these systems and a dipole moment function for the X2Σ+ state were generated from high level ab initio calculations and have been used in Le Roy’s level program to produce transition dipole moment matrix elements (including their J dependence) for a large number of vibrational bands. The program pgopher was used to calculate Einstein A coefficients, and a line list was generated containing the observed and calculated wavenumbers, Einstein A coefficients and f-values for 290 bands of the A2Π–X2Σ+ transition with v′ = 0–22, v′′ = 0–15, 250 bands of the B2Σ+–X2Σ+ transition with v′ = 0–15, v′′ = 0–15 and 120 bands of the rovibrational transitions within the X2Σ+ state with v = 0–15. The Einstein A coefficients have been used to compute radiative lifetimes of several vibrational levels of the A2Π and B2Σ+ states and the values compared with those available from previous experimental and theoretical studies.