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SPECTROSCOPY OF HYDROGEN AND WATER CLUSTERS IN
HELIUM DROPLETS
by
Kirils Kujanovs
A Dissertation presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(CHEMISTRY)
August 2007
Copyright 2007 Kirils Kujanovs
Object Description
| Title | Spectroscopy of hydrogen and water clusters in helium droplets |
| Author | Kujanovs, Kirils |
| Author email | kuyanov@usc.edu |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Chemistry (Chemical Physics) |
| School | College of Letters, Arts and Sciences |
| Date defended/completed | 2007-03-29 |
| Date submitted | 2007 |
| Restricted until | Restricted until 3 Aug. 2008. |
| Date published | 2008-08-03 |
| Advisor (committee chair) | Vilesov, Andrey F. |
| Advisor (committee member) |
Bradforth, Stephen E. Kresin, Vitaly |
| Abstract | Hydrogen and water clusters were studied by means of Coherent Anti-Stokes Raman Scattering (CARS) and infrared spectroscopy, respectively. The helium droplet encapsulation technique was used in these experiments.; The experiments with large para-hydrogen clusters of several thousand molecules per cluster embedded in helium droplets are presented. CARS spectra of hydrogen clusters with different ratios of ortho- and para- hydrogen are analyzed in terms of band intensities and frequencies. The CARS experimental setup and helium droplet apparatus are thoroughly described.; Small water clusters of 2 to 30 molecules per cluster as well as water monomers were studied in helium droplets. Rotational constants and rotational and vibrational relaxation times of single water molecules in helium droplets were deduced from the analysis of their depletion spectra. The method of studying the infrared intensities of molecules and molecular clusters was developed by using the helium droplet encapsulation technique. The method was applied to study the non-additive enhancement of the infrared intensity in water clusters of 2, 3 and 4 molecules. Gradual transformation of the spectra from a relatively narrow band of small clusters to a broad spectrum, characteristic for bulk ice, was observed.; The solid para-hydrogen Raman Shifter that was developed in our laboratory is described in one of the Chapters. This device utilizes the para-hydrogen crystal at T = 4 K as a medium for Stimulated Raman Scattering (SRS). The near-infrared laser was focused into the crystal and the red-shifted Stokes wave was obtained from the SRS process. This device provides mid-infrared laser radiation in the range of 4.4 - 8 µm to study heavy atom vibrations in molecules. The grow-from-the-liquid technique that was used here gives clear para-hydrogen crystals with a high laser damage threshold. |
| Keyword | Superfluidity; Superfluid hydrogen; Superfluid para-hydrogen; water clusters; infrared intensity; Raman shifter; helium droplets; CARS; Coherent Anti-Stokes Raman Scattering; Coherent Anti-Stokes Raman Spectroscopy; para-hydrogen; hydrogen; water; helium |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Type | texts |
| Legacy record ID | usctheses-m759 |
| Rights | Kujanovs, Kirils |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | http://www.usc.edu/isd/libraries/services/ask_a_librarian/email/ |
| Filename | etd-Kujanovs-20070803 |
| Archival file | uscthesesreloadpub_Volume44/etd-Kujanovs-20070803.pdf |
Description
| Title | Page 1 |
| Full text | SPECTROSCOPY OF HYDROGEN AND WATER CLUSTERS IN HELIUM DROPLETS by Kirils Kujanovs A Dissertation presented to the FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (CHEMISTRY) August 2007 Copyright 2007 Kirils Kujanovs |
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