A buffer gas cooled molecular beam apparatus for chirped pulse millimeter wave spectroscopy

An apparatus that utilizes buffer gas cooling to produce slow atomic (Ba, Ca) and molecular (BaF, CaF) beams is constructed. In-cell temperatures of 20 ± 0.25K are achieved with chamber cooldown times of under two hours. Laser Induced Fluorescence (LIF) spectra of BaF and CaF confirmed thermalization of the molecular beam to the temperature of the buffer gas and additional hydrodynamic cooling to rotational and translational temperatures under 10K. Laser fluence effects on the intensity of barium and calcium ablation were studied and used to optimize laser parameters for maximum ablation of the desired species. A chirped pulse millimeter wave (CPmmW) setup was combined with the buffer gas cooling apparatus for combined laser and millimeter wave spectroscopy experiments of Rydberg states. LabVIEW programming is used for an internal temperature feedback system, raster scanning of the ablation target, as well as millimeter wave FID signal digital acquisition. Use of the apparatus for chirped pulse microwave spectroscopy of buffer gas cooled beams have led to orders of magnitude improvement in both the resolution and the reduction of time required to record molecular Rydberg spectra.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2015

Author dc:creator

• Klein, Ethan Avram

Advisor dc:contributor.advisor

• Robert W. Field.

• Chemistry.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/98781

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/98781