Detection and probing of nitric oxide (NO) by two-colour laser photoionisation (REMPI) spectroscopy on the A ← X transition

A simple two-colour (1 + 1′) REMPI scheme for the detection and probing of nitric oxide (NO) via the A2Σ+ ← X2 Π transition has been introduced and characterised. Pulsed 226 and 308 nm laser light derived from a XeCl excimer pump laser has been used for resonant excitation and photoionisation. The two-colour (1 + 1′) ReMPI scheme has been found to offer substantially higher sensitivity than the conventional one-colour scheme. The reasons for this improvement and other advantages of the two-colour technique for the state-resolved probing of NO(X) are outlined.