A joint theoretical-experimental investigation of the lower bound states of the NO(X-2 Pi)-Ar complex

In an extension of recent work [Y. Kim, K. Patton, J. Fleniken, and H. Meye r, Chem. Phys. Lett. 318, 522 (2000)], overtone pumping followed by resonan tly enhanced multiphoton ionization (REMPI) detection is used to record spe ctra corresponding to excitation of the lowest five bend-stretch vibrationa l levels of the NO(X (2)Pi,v=2)-Ar complex. High-quality ab initio potentia l energy surfaces, coupled-electron-pair (CEPA) and coupled cluster single double triple [CCSD(T)], are used to predict the positions of these same fi ve states, but in the NO(X (2)Pi,v=0)-Ar complex. The vibrational wave func tions and basis set expansion coefficients, determined within the adiabatic bender model, are then used to simulate the observed spectrum for excitati on of the NO(X (2)Pi, v=2)-Ar complex. The overall position and rotational substructure matches the experiment extremely well, particularly when the s imulation is based on the presumably more accurate CCSD(T) potential energy surfaces. (C) 2000 American Institute of Physics. [S0021- 9606(00)00125-2] .