Structure and predissociation of electronically excited HgN2 complex

Abstract

The structure and the predissociation dynamics of an excited van der Waals (vdW) complex HgN2 which is produced in a supersonic jet, have been investigated by means of laser-induced fluorescence (LIF) spectroscopy. The vibronic systems of the A-X and B-X transitions are analyzed in terms of the vdW bond stretching and the Hg-N2 bending modes. The predissociation process, HgN2 (A or B) → Hg(3P0) + N 2, in both of the A and B vibronic states has also been discussed by detecting Hg(3P0) as a predissociation product. Assignment of vibrational quantum numbers for the vdW bond stretching mode is made on the basis of the observed splittings among isotopic species for mHgN 2 (m = 198, 199, 200, 201, 202, and 204). Rotational contour analysis of the LIF and the 3P0 formation spectra is performed to determine (1) the branching ratio for the fluorescence and the predissociation processes as a function of vibrational and rotational quantum numbers and (2) potential functions for the A and B states along the vdW bond coordinate. The dissociation energies of the complex in the A and B states are determined to be 660(77) and 41(8) cm-1, respectively, and the equilibrium distances between Hg and c.m. of N2 are 3.08(2) and 5.37(10) Å for the respective two states. Based on the simulation of the Franck-Condon profile of the bending progressions for the A-X band, the equilibrium configurations for the X and A states are estimated to be T shaped and linear, respectively. © 1988 American Institute of Physics.