Molecular orbital calculation for polymeric beryllium hydride, polyethlene, and polymeric boron hydride according to the pseudo-lattice method

Abstract

The pseudolattice calculations in the CNDO/2 level of approximation are carried out for polymeric beryllium hydride, polyethylene, and polymeric boron hydride. Since there is no evidence on the geometry for polymeric boron hydride, the two possible geometries are assumed. One is a polyethylene-type geometry and the other is a polymeric beryllium hydride-type geometry. In order to examine the reliability of the pseudolattice method applied to polymeric systems and to compare their relative stability, we calculate polyethylene and polymeric beryllium hydride and then compare with polymeric boron hydride having the assumed structures. The total energy calculation indicates that a polymeric beryllium hydride-type geometry is more stable than a polyethylene-type geometry. Our results obtained for polyethylene are in good agreement with those given by CNDO/2 crystal orbitals. Though we used the CNDO/2 approximation, ionization potential, electron affinity, and energy gap are in good agreement with those of ab initio calculations. From the convergence problem with respect to the number of unit cells (M), the calculation with value of 4 for M can be considered to give the convergence limit results.