All the nonadiabatic (J=0) bound states of NO2

We calculated all 3170 A(1) and B-2 (J = 0) vibronic bound states of the co upled electronic ground ((X) over tilde (2)A(1)) and the first excited ((A) over tilde B-2(2)) surfaces of NO2, using a modification of the ab initio potentials of Leonardi et al. [J. Chem. Phys. 105, 9051 (1996)]. The calcul ation was performed by harmonic inversion of the Chebyshev correlation func tion generated from a DVR Hamiltonian in Radau coordinates. The rms error o f the eigenenergies is about 2.5 cm(-1), corresponding to a relative error of 10(-4) near the dissociation energy. The results are compared with the a diabatic and diabatic levels calculated from the same surfaces, with experi mental data, and with some approximations for the number of states function N(E). The experimental levels are reproduced fairly well up to an energy o f 12 000 cm(-1) above the potential minimum while the total number of bound levels agrees to within 2% with that calculated from the phase space volum e. (C) 1999 American Institute of Physics. [S0021-9606(99)01507-X].