The vibrational structure of the *B1 + *Al systc.m of NO% has been assigned to a progression in vi. Vibrational analyses for three isotopic species have been made using a hamiltonian which allows esplicitly fore largeamplitude bendingvibration.
The system origin for the normal isotopic species has been assigned an extrapolated value of 14743.5 cm-'. The bending potential function is expressed as a rapidly converging Taylor series cspnnsion about the linens conftguratior.. Thcrc is no evidence that the equilibrium configuration is nonlinear.
The low-lying 'B, system of' NO, was discovered by Douglas and Huber [l] in 1965. These authors were able to analyze the rotational structure of a series of strong bands arising from transitions to K' = 0 in the region 3700-4600 A. They were unable to characterize the geometry or vibrational numbering of the excited state, however, since the observed transitions are far from the system origin.
Recent advances in our understanding of the bending hamiltonian for triatomic molecules [2,3] now make it feasible to extrapolate from high vibrational quanta to obtain an expression for the upper state potential function. Assuming, as did Douglas and Huber, that the observed bands arise from a single progression in the upper state bending vibration, we have caiculated potential functions for the 'B, states of three isotopic species of NO,, using published data [l] for 14N1602 and UN1G02, and data obtained in this laboratory for 14N1802.
N1*02 (90.2 atom %) was obtained,from Milcs-Yeda, Inc. and was used without further purification. Spe&a were recorded photographically at high resolution using a Jarrell-Ash 3.4 m Ebert monochromator in the 11th and 12th orders calibrated from an iron hollow cathode discharge. Dispel sion was approximately 2 mm/A.