The interaction of rotation and local mode tunneling in the overtone spectra of symmetric hydrides. II. The spatial properties of the XH4 eigenstates

Abstract

The matrix elements of the XH4 rotation-tunneling Hamiltonian are given for basis states with all of the vibrational excitation in a single bond. A basis set of symmetrized rovibrational wave functions is given that are eigenfunctions in the limit in which the local mode tunneling rate is much smaller than the rotational precession rate. Using this basis, it is demonstrated that, in this limit, vibrational tunneling occurs with a simultaneous reorientation of the molecule, such that the spatial properties of the excited bond are the same as if tunneling did not take place at all. A resonant two-photon dissociation experiment is proposed that could observe this effect. It is found that as one moves away from this limit, the polarization properties of the F2 symmetry vibrational state retain much of the symmetric top structure.