Spectral Taxonomy: A Semi-automated Combination Of Chirped-pulse And Cavity Fourier Transform Microwave Spectroscopy

Crabtree, Kyle N.

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https://hdl.handle.net/2142/51004 Copy

Description

Title

Spectral Taxonomy: A Semi-automated Combination Of Chirped-pulse And Cavity Fourier Transform Microwave Spectroscopy

Author(s)

Crabtree, Kyle N.

Contributor(s)

McCarthy, Michael C.

Issue Date

2014-06-19

Keyword(s)

Chirped pulse

Abstract

"Chirped-pulse Fourier transform microwave spectroscopy (CP-FTMW) has proven to be a powerful tool for broadband spectral surveys in the cm-wave band. In conjunction with a non-specific production source, such as an electrical discharge, new, unexpected molecules can be detected by their rotational spectra provided that they can be disentangled from other species that may be present. As an example, we have recently used a CP-FTMW spectrometer operating in the 8--18 GHz band to detect and identify two new silicon nitrides, HSiNSi and H$_3$SiNSi, in a discharge of dilute silane and nitrogen, although neither species had been the subject of prior experimental or theoretical study. However, of the $\sim$100 lines that are observed in this plasma, only $\sim$20 have been assigned to known species. To further investigate unassigned lines in CP-FTMW spectra, we take advantage of the higher sensitivity of a traditional cavity FTMW spectrometer to rapidly perform follow-up assays in an approach we call ""spectral taxonomy."" Lines are classified according to whether their intensities are significantly altered by, for instance, turning off the discharge, applying a magnetic field, or removing a precursor gas; lines that show the same behavior for all tests may arise from a common carrier. After taxonometric classification, lines within each group are exhaustively tested with double resonance methods in an attempt to establish linkages which would identify lines arising from a shared quantum state and give clues as to the structure of the carrier. Using newly-designed control software for our cavity spectrometer, this entire procedure can be performed with minimal human intervention."

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/51004

DOI

https://doi.org/10.15278/isms.2014.RE03

Copyright and License Information

Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/

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