High resolution pulsed-cw double-resonance spectroscopy on the B1Σ+(ν′=0) « A1П(ν″=0) system of CO

A 2 + 1 double-resonance laser-induced fluorescence technique is described in which the high power of a pulsed laser is combined with the narrow bandwidth of a single-mode cw ring dye laser. The combination of these laser systems allows the study of highly excited states with MHz resolution. This double-resonance technique has been applied to the study of the B1Σ+(ν′=0) « A1П(ν″=0) system of CO. From the high resolution spectra the term value of the A state could be determined, T= 64748.0091 ± 0.0019 cm−1, corresponding to an increased accuracy over previously reported values by an order of magnitude.