title: Accurate and highly efficient calculation of the highly excited pure OH stretching resonances of O(1D)HCl, using a combination of methods.
abstract: Accurate calculation of the energies and widths of the resonances of HOCl--an important intermediate in the O(1D)HCl reactive system--poses a challenging benchmark for computational methods. The need for very large direct product basis sets, combined with an extremely high density of states, results in difficult convergence for iterative methods. A recent calculation of the highly excited OH stretch mode resonances using the filter diagonalization method, for example, required 462,000 basis functions, and 180,000 iterations. In contrast, using a combination of new methods, we are able to compute the same resonance states 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 are observed for calculations of the high-lying bound states, as reported in a previous paper [J. Theo. Comput. Chem. 2, 583 (2003)].
authors.affiliation: Department of Chemistry and Biochemistry and Department of Physics, Texas Tech University, Lubbock, Texas 79409-1061, USA.
authors.forename: Wensheng
authors.initials: W
authors.lastname: Bian
authors.forename: Bill
authors.initials: B
authors.lastname: Poirier
mesh_terms: D003198:Computer Simulation; D006851:Hydrochloric Acid / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D010100:Oxygen / Q000737:chemistry*
chemical_list: D017665:Hydroxyl Radical; D006859:Hydrogen; D006851:Hydrochloric Acid; D010100:Oxygen