Resonance-enhanced multiphoton ionisation of vibrational state selected NH3 molecules: a reinvestigation

Abstract

The unexpected and incompletely explained results obtained by T. Seelemann, P. Andresen and E. W. Rothe (Chem. Phys. Lett., 1988, 146, 89) when attempting 2 + 1 resonance-enhanced multiphoton ionisation on NH₃ molecules prepared in the 3¹4¹ combination level of the ground electronic state have been rationalised in terms of a local perturbation. This perturbation is shown to mix the J″= 6, K″= 5, I=– 1 state of the X 3¹4¹(E′) level and the J″= 6, K″= 3 state of an A^′₁ vibrational level which we tentatively assign as the symmetric inversion component of the 1¹2² combination mode of the ground state.