Calculating quasi-bound rotation-vibrational states of HOCl using massively parallel computers

We calculate positions and predissociation widths for quasi-bound states of HOCl with total angular momentum of J=0 and J=3. An ab initio potential energy surface is used in conjunction with a complex absorbing potential (CAP). These calculations are performed by diagonalising a complex symmetric Hamiltonian using our discrete variable representation (DVR) based parallel code, PDVR3D, and a truncation and diagonalisation algorithm. The resonances are identified as those states in the continuum, which are stable with respect to CAP and basis set parameters. Test on the resonances are carried out using over 90 different absorbing potential heights. Resonances of both Feshbach (vibrational trapping) and shape (rotational trapping) are identified.