Development of Frequency Comb Velocity-Modulation Spectroscopy, Spectroscopy of HfF+ and the JILA eEDM Experiment

<p>Broad bandwidth, precision spectroscopy of the molecular ions of interest to the JILA electron electric dipole moment experiment, HfF+ and ThF+, is necessary due to the limited amount of spectroscopic information available and the large theoretical uncertainties in the energy level structure (thousands of wavenumbers). This thesis covers the development of a novel spectroscopic technique, frequency comb velocity-modulation spectroscopy, that provides high resolution, broad spectral bandwidth, ion discrimination and high sensitivity simultaneously. Frequency comb velocity-modulation spectroscopy as well as singlefrequency velocity-modulation spectroscopy have been used to identify ve rotational bands of HfF+. This work discusses the rst spectroscopic information for HfF+ which came from our measurement of the <sup>1</sup>Π<sub>1</sub>-<sup>1</sup>Σ+ (0,0) band recorded with single-frequency velocity modulation spectroscopy with a sensitivity of 3x10<sup>-7</sup> Hz<sup>-1/2</sup>. The development of frequency comb velocity-modulation spectroscopy allowed us to cover a thousand wavenumbers of spectral bandwidth and to identify an additional four HfF+ bands. The achieved sensitivity for frequency-comb velocity-modulation spectroscopy was 4x10<sup>-8</sup> Hz<sup>-1/2</sup> (spectral element)<sup>-1/2</sup> with 1500 simultaneous detection channels spanning 150 cm-1 of bandwidth. For a 30 minute acquisition time using 30 interleaved images to densely sample the whole spectrum, this corresponded to a 3x10<sup>-7</sup> single-pass fractional absorption sensitivity for each of the 45,000 measurement channels. The spectroscopic information from all five HfF+ rotational bands is presented and molecular constants for the <sup>1</sup>Σ<sup>+</sup>, <sup>3</sup>Π<sub>1</sub>, and <sup>1</sup>Π<sub>1</sub> states were extracted.</p>
Year of Publication
University of Colorado Boulder
Advisors - JILA Fellows