2+1 resonance-enhanced multiphoton ionisation spectroscopy of the high nu(2) levels of the (B)over-tilde(1)E '' Rydberg state of NH3(ND3)

2+1 resonance-enhanced multiphoton ionisation spectra of the (B) over tilde E-1 "-(X) over tilde (1)A(1) 2(0)(n) (n greater than or equal to 6) transi tions of NH3(ND3) have been recorded, and the room temperature spectra rota tionally analysed. The variation with nu (2) of the spectroscopic parameter s is discussed. An increased rate of predissociation is observed for the 2( 0)(11) and 2(0)(12) bands of NH3. This is attributed to anon-adriabatic int eraction with a nearby state of A(2)" most probably the (D) over tilde'(1)A (2)" (4sa(1)') Rydberg stare enhancing the rate of the known (B) over tilde E-1 " --> (A) over tilde (1)A(2)" (C) 2000 Elsevier Science B.V. All right s reserved.