Potential energy surfaces of low-lying states of the aluminum trimer

Abstract

The potential energy surfaces for the low-lying states of the Al 3 molecule have been investigated by means of Hartree-Fock CI calculations. Four states are candidates for the ground state: an acute isosceles triangle 4B 1, an obtuse isosceles triangle 4A 2, and two nearly equilateral triangles, 2B 1 and 2A 1. The ground state is found to be 4B 1, but because of the very small energy separating the four states they can be considered as nearly degenerate. A partial vibrational analysis has been carried out considering only the totally symmetric modes of the C 2v point group in order to show the different nature of the corresponding potential energy surfaces.