Nonadiabatic Predissociation Studies of the (1-3) 3Π g System of Al 2 by Means of a Complex Rotated Finite Element Method

Abstract

A general numerical Runge–Kutta–Fehlberg based diabatization procedure for electronic states in diatomics was applied to the adiabatic (1-3) 3Π g system of Al 2 in order to obtain a strictly diabatic basis. Using an exterior complex rotated finite element method, adiabatic Born–Oppenheimer (BO) as well as diabatic rovibronic term energy values and predissociation widths for the (2) 3Π g ; ( v, N)=(0−50, 0−25) and (3) 3Π g ; ( v, N)=(0−17, 0−25) levels were computed. Comparing rotationless BO and diabatic energies, differences between 10 and 25 cm −1 are found for the (2) 3Π g levels while the (3) 3Π g levels display an almost constant shift ∼12 cm −1. From the widths, the nonradiative lifetime for each rovibronic level was calculated. Based on existing rotationless radiative lifetimes, an estimation of an upper limit of about 50 ns was used to determine a number of rovibronic (2, 3) 3Π g levels which may be experimentally observed.