Transition probabilities and average cross sections for the Na 2B1Π u→ X1Σ +g system using as excitation the 4880 Å Ar + laser line

Abstract

The fluorescence spectrum of Na 2 induced by the 4879.86 Å line of an Argon ion laser has been analyzed with special emphasis on determination of accurate relative intensities. We have observed nineteen fluorescence series for the B 1Π u → X 1Σ g + band system. Some series are reported for the first time. The radiative transition probabilities for the observed fluorescence series were calculated using hybrid potential energy curves for the B 1Π u and X 1Σ g + states constructed up to dissociation and a B– X transition dipole moment function. Radiative lifetimes for the rovibrational levels of the upper states pumped by the laser line have also been calculated. The transition probabilities and lifetimes agree with the corresponding observed measurements usually within the experimental uncertainty. From the rotational satellite structure with Δ J′=±1, ±2 . . . ±20, for some v′′-bands of the most intense fluorescence series induced by emission from the vibrational-rotational levels: v′=6, J′=43 and v′=9, J′=56, collision-induced transition rates and average cross sections have been obtained.