Deperturbation at high pressure and in matrices

The purpose of a deperturbation calculation is to define a computational model that faithfully reproduces every detail of observable spectra in terms of deper-turbed potential energy curves and the interaction terms that axe responsible for the perturbation. Deperturbation calculations can be extremely complicated. When faced with such a calculation, one is tempted to doubt whether a specific set of deperturbed potentials has any physical significance. 

Because of the considerably larger size [Eq. (5.2.1)] of Rydberg ((r)3p = 3.7 A) than valence ((r)2p = 2.6 A) orbitals, Rydberg states have much larger pressure broadening cross-sections than valence states, as shown in the following data at 5 bar neon (Miladi, et al, 1978)  

Chergui, et al, (1985) have used synchrotron radiation to observe the NO C2n state in an argon matrix and found the C2II(u = 1) level near 61,500 cm-1 

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