2+1 resonance-enhanced multiphoton ionisation spectroscopy of the high ν2 levels of the [formula omitted] Rydberg state of NH 3(ND 3)

Abstract

2+1 resonance-enhanced multiphoton ionisation spectra of the B ̃ 1 E″– X ̃ 1 A 1 2 0 n (n⩾6) transitions of NH 3(ND 3) have been recorded, and the room temperature spectra rotationally analysed. The variation with ν 2 of the spectroscopic parameters is discussed. An increased rate of predissociation is observed for the 2 0 11 and 2 0 12 bands of NH 3. This is attributed to a non-adiabatic interaction with a nearby state of A 2″ electronic symmetry, most probably the D ̃ ′1 A 2″ (4 sa 1 ′) Rydberg state enhancing the rate of the known B ̃ 1 E″⇒ A ̃ 1 A 2″ predissociation mechanism.