Date of Award

Spring 1-1-2011

Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Eric A. Cornell

Second Advisor

Jun Ye

Third Advisor

Heather Lewandowski


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 single frequency velocity-modulation spectroscopy have been used to identify five rotational bands of HfF+. This work discusses the first spectroscopic information for HfF+ which came from our measurement of the 1Π1 1Σ+ (0,0) band recorded with single-frequency velocity modulation spectroscopy with a sensitivity of 3x10-7 Hz-1/2. 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 4x10-8 Hz-1/2 (spectral element)-1/2 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 3x10-7 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 1Σ+, 3Π1, and 1Π1 states were extracted.