Accurate and highly efficient calculation of the highly excited pure OH stretching resonances of O(¹D)HCl, using a combination of methods

An accurate and highly efficient calculation of the (7,0,0) and (8,0,0) resonance states of HOCL, which are states for which the OH bond is selectively and highly efficient was performed. The effectiveness of the one-state-at-a-time approach for computing selected mode- and state-specific resonances was evaluated. It found that the same resonance states can be computed to higher accuracy with a basis less than half the size, using only a few hundred iterations-although the CPU cost per iteration is substantially greater. Similar performance enhancements were observed for calculations of the high-lying bound states.