OVERVIEW

Optimized geometry structures, total energies, infrared spectra, thermodynamics parameters of lanthanide hydrides and the reaction between lanthanide atom and hydrogen atom are studied use effective core potentials. Results indicate that lanthanide contract phenomenon are effected the bond lengths of lanthanide hydride. Most of lanthanide hydride will release heat (except for monohydrides of Tm and Yb) in the reaction. All of the calculated vibrating frequencies of lanthanide hydrides are positive. Most of the trihydride are stable than dihydride except for Yb. Bond orbits in lanthanide hydrides are mainly contributed by s and d compounds, there are much more f compound in lanthanide trihydride molecular.

Keywords: Lanthanide, Hydride, Effective core potential

1 INTRODUCTION

A large progress on lanthanide chemistry study had been made in recent ten years. There are many experimental studies on lanthanide compounds, complex and organometallics ^{[1 6]}. But the theoretical study deal with lanthanide has lagged behind experimental study, due in large part to well known computational problems ^[7 ^,8 ^] , such as large numbers of orbits and electrons, the importance of relativistic and electron correlation effects.

Several computational approaches have been pursued for the lanthanides, including the extended Huckel studies of Hoffmann et al. [9], semiempirical applications[10], ab initio treatments of workers such as Pyykko[11], and effective core potentials (ECPs)[12 ^,13 ^]. There are a few...