PLANE-WAVES BASIS SEAS IN THE DESCRIPTION OF DIATOMIC ANIONS AND VALENCE CHARGE-DENSITY

The performance of plane wave basis sets to describe bond lengths, and Vibrational frequencies for diatomic anions is described within the c ontext of ab initio total energy density functional pseudopotential me thod. Also, the behavior of the charge density as a function of the pl ane wave expansion size is studied for a molecule containing C, H, O, N, and S atoms. For the three properties studied, a critical size of t he basis set that assures a reasonable description of them was found. These critical values are around a cutoff energy of at least 20 Ry bel ow the cutoff energy used to design the pseudopotentials. (C) 1996 Ame rican Institute of Physics.