AN ABINITIO MOLECULAR-ORBITAL STUDY OF THE THERMAL-DECOMPOSITION MECHANISMS OF C2H5ASH2 AND C2H5GAH2

Ab initio molecular orbital calculations were used to study the pyrolysis of ethylarsine and ethylgallane. Within the computational models selected, the dominant decomposition channel for ethylarsine was found to be the unimolecular elimination of ethane, which requires approximately 55.0 kcal/mol. However, an ethyl free radical mechanism requiring 56.0 kcal/mol was found to be competitive. The dominant decomposition channel for ethylgallane was found to be the beta-elimination of ethylene, which has a barrier of only 35.8 kcal/mol. In this case alternative decomposition channels all required more than 60 kcal/mol.