Electronic characterization techniques band vibrational structure

Spectroscopic Basics of Nas C. In the late 1980s special interest was focused on the C(2) E" state (in Dsh symmetry) of Nas. Energy-resolved spectroscopy allowed the observation of lower vibrational levels of this electronic state by means of TPI, whereas the upper levels require the use of DS to probe dissociative states [369, 374, 393]. The spectrum of the C state is characterized by a vibrational band structure with pseudorotational features, as shown in Fig. 4.3. These investigations confirmed the C state to be partially predissociated. Therefore, the dissociation channel was proposed to be the main relaxation process for states higher in energy than the C state. This could also be demonstrated for the D state by the depletion technique with a few nanoseconds time resolution [375], as well as for Rydberg states close to the ionization limit [124]. 

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