Previously we searched for the ab initio global minima of several SixHy clusters by a genetic algorithm in which we used the AM1 semiempirical method to facilitate a rapid energy calculation for the many different cluster geometries explored. However, we found that the AM1 energy ranking significantly differs from the ab initio energy ranking. To better guarantee locating the ab initio global m...

This paper describes a hybrid ab initio quantum mechanical/molecular mechanics (QM/MM) method for calculating activation free energies of chemical reactions in solution, using molecular mechanics force fields for the solvent and an ab initio technique that incorporates the potential from the solvent in its Hamiltonian for the solute. The empirical valence bond (EVB) method is used as a referenc...

There has been a significant progress in ab initio approaches to the structure of light nuclei. Starting from realistic twoand three-nucleon interactions the ab initio no-core shell model (NCSM) can predict low-lying levels in p-shell nuclei. It is a challenging task to extend ab initio methods to describe nuclear reactions. In this contribution, we present a brief overview of the the first ste...

a computational study of the electronic structure and stability of complexes formed between zeolite y and boric acid was carried out at the hf and b3lyp levels using 6-31g* basis set. five structures located as local minimum in pes of complex (structures d, e, f, g, and h). the most stable structure is formed due to hydrogen bonding between two hydroxyl of boric acid and both oxygen of ...

The work presented in this thesis concerns the production of high-temperature spectroscopic line lists for the SO2 and SO3 molecules, for the purposes of astrophysical, terrestrial and industrial applications. Both line lists are computed using ab initio computational methods to calculate rovibrational energy levels and dipole moment transition intensities. The hot SO2 line list is computed usi...