Computation of large systems with an economic basis set:: Ab initio calculations of silicon oxide clusters

Silicon oxide plays an important role in many technological areas. Extensive ab initio calculations for related systems are thus desired but are limited due to the requirement of a huge computation resource. We show here that an economic basis set can be used to determine reliable atomic and electronic structures of the silicon oxide system. Binding energies in a single-point energy calculation using a standard higher-level basis set on the geometric structures optimized with the economic basis set found reasonable agreement with reported ones of high-level calculations. The approach has enabled the computation of silicon oxide clusters as large as 16 atoms being performed with considerably high accuracy using a medium level of computation resources. (C) 2001 American Institute of Physics.