摘要:
                                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)+N2, 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 mHgN2 (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.