We present the first nonempirically calculated spectroscopic constants for the recently observed [J. Chem. Phys. 105, 2167 (1996)] ground (X (2) Sigma(+)) and excited (A (2) Pi) states of Sr+Ar. Our best results yield D-e = 694 cm(-1), R-e = 3.662 Angstrom, and omega(e) = 38.7 cm(-1) for the ground and D-e = 1967 cm(-1), R-e = 3.169 Angstrom, and omega(e) = 99.1 cm(-1) for the excited state. The calculated D-e's are within the error bars of the experimentally determined one for the ground state favoring the low end and underestimate the corresponding one for the excited state by about 7% The equilibrium separations (R-e's) for the two states have not been experimentally determined, however our results accurately reproduce the estimated shift, Delta R-e, between the two states. The interaction is mainly electrostatic for the ground state for which the contribution of dynamic electron correlation was found to be more important than for the excited state. (C) 1997 American Institute of Physics.