Rotationally resolved electronic spectroscopy of 6-methylindole: Structures, transition moments, and permanent dipole moments of ground and excited singlet states

Abstract

The rotationally resolved electronic spectrum of the S1←S0 electronic origin band of 6-methylindole (6-MI) has been measured in a molecular beam and has been fit to rigid asymmetric rotor Hamiltonians in both electronic states using evolutionary strategies. Rotational constants, dipole moments in both electronic states, and orientation of the transition dipole moment in the inertial frame of the molecule have been determined and compared to the results of ab initio calculations. Both the values of the permanent dipole moments as of the transition dipole moment point to an Lb-state as lowest electronically excited state in 6-MI.