Toward pure electronic spectroscopy

Abstract

In this thesis is summarized the progress toward completing our understanding of the Rydberg system of CaF and developing Pure Electronic Spectroscopy. The Rydberg system of CaF possesses a paradigmatic character due to its strongly polar ion-core. The first characterization of the Stark effect in a Rydberg system of this nature is presented here, and a diagnostic application of the Stark effect for making assignments of N+ and f quantum numbers has been demonstrated. In addition, a general method, which relies on polarization diagnostics and is applicable not only to studies of Rydberg states, for making unambiguous rotational assignments in the absence of rotational combination differences, has been described for the case of unresolved doublet states. New information, obtained using the Stark effect and polarization diagnostics, has furthered our knowledge of the partially core-penetrating character of nominally core-nonpenetrating states. In order to systematically obtain the same information that is contained in a Stark effect spectrum, but with less difficulty, we are developing experimental methods to record same-n* Rydberg-Rydberg transitions directly, using Time Domain THz and Chirped-Pulse Microwave Spectroscopies. In both of these methods, the spectrum is recorded in the time domain, which results in reliable relative transition intensities. We show that the relative transition intensities in a Rydberg-Rydberg spectrum provide information that permits separation of different interaction mechanisms between the Rydberg electron and the ion-core.