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The 2+1 multiphoton ionization spectrum of the C'-X transition in NH3

This example is taken from "The resonance enhanced multiphoton ionization spectroscopy of ammonia isotopomers NH3, NH2D, NHD2 and ND3", M. Nolde, K.-M. Weitzel and C. M. Western, Phys. Chem. Chem. Phys. 7, 1527 (2005) http://dx.doi.org/10.1039/b417835c.

Data file: nh3c0x0.pgo

The data file simulates the origin band of the C'-X 2 + 1 multiphoton transition in NH3. See the paper for the constants used; note the ground state constants are not the best available but are adequate for the Doppler limited resolution. There are two points that are slightly non-standard:
  1. The point group used is D3h, rather than C3v. This is necessary to account for the inversion doubling in the ground state.
  2. There are two spherical tensor transition moments contributing to the transition, a zero rank component, <v=0|T(0,0)|v=0> and a second rank component <v=0|T(2,0)|v=0>

The picture below shows a simulation at 300K.