Ab initio calculations on the dissociative reaction of As-4 molecules

The dissociation of an As-4 molecule in vacuum was studied. At first, we ca lculated the energy for the dissociation of one As-4 molecule without the r estriction of symmetry and it is found that the energy barrier of the react ion path is smaller than that reported previously. Next. we calculated the dissociation of an As-4 molecule under interaction with another As-4 molecu le and found that this energy barrier is smaller than that of the former. T his means that at high As-4 pressure, two As-4 molecules react and give As- 2 molecules which agrees with the model given by Foxon and Joyce in molecul ar beam epitaxy (MBE) of GaAs. (C) 2000 Elsevier Science B.V. All rights re served. PACS: 31.15 Ar: 81.15.Hi; 82.30.Lp.