The X-2 Sigma(+), A(2) Pi, B-2 Sigma(+) C-2 Sigma(+) states of LiAr an
d the ground state of LiAr+ are calculated by configuration interactio
n methods. The existence of a double potential well is found for the C
-2 Sigma(+) state. The origin of the double well is surmised to lie in
the existence of a nodal plane separating two radial regions of the e
lectron density in the Rydberg atomic orbital. The spectroscopic const
ants and the transition properties between the calculated states are a
lso reported. (C) 1997 Elsevier Science B.V.