Laser-induced fluorescence spectroscopy of Hg2 excimers

Abstract

Pump-and-probe methods were used to excite high-lying I ( O u + ) and J(1 u ) states of Hg2, whose transitions to various lower states cause emission of fluorescence bands centered at 420 nm ( J 1 u → AO g ± ) , 513 nm (J1 u → E2 g ), 632.6 nm (J1 u → F1 g ), 451.4 nm ( I O u + → B 1 g ) , and 422.6 nm ( I O u + → A O g + ) . The transitions from I O u + and J(1 u ) to the repulsive X O g + ground state give rise to Condon internal diffraction patterns. A comprehensive investigation of the fluorescence bands and of the corresponding excitation spectra, some of which overlap, permitted unambiguous assignment of the bands to transitions between particular electronic states whose positions were located on the potential energy diagram. The experiment yielded vibrational constants for the molecular states as well as qualitative information about the relative internuclear separations for the various states.