A K_a-band chirped-pulse Fourier transform microwave spectrometer

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• 作者：Daniel P. Zaleski ; Justin L. Neill ; Matt T. Muckle ; Nathan A. Seifert ; P. Br ; on Carroll ; Susanna L. Widicus Weaver ; Brooks H. Pate
• 关键词：Broadband spectroscopy ; Microwave spectroscopy ; Acetaldehyde ; Ethyl formate
• 刊名：Journal of Molecular Spectroscopy
• 出版年：2012
• 出版时间：October, 2012
• 年：2012
• 卷：280
• 期：Complete
• 页码：68-76
• 全文大小：786 K

文摘

The design and performance of a new chirped-pulse Fourier transform microwave (CP-FTMW) spectrometer operating from 25 to 40 GHz (K_a-band) is presented. This spectrometer is well-suited for the study of complex organic molecules of astronomical interest in the size range of 6-10 atoms that have strong rotational transitions in K_a-band under pulsed jet sample conditions (T_rot = 1-10 K). The spectrometer permits acquisition of the full spectral band in a single data acquisition event. Sensitivity is enhanced by using two pulsed jet sources and acquiring 10 broadband measurements for each sample injection cycle. The spectrometer performance is benchmarked by measuring the pure rotational spectrum of several isotopologues of acetaldehyde in natural abundance. The rotational spectra of the singly substituted ¹³C and ¹⁸O isotopologues of the two lowest energy conformers of ethyl formate have been analyzed and the resulting substitution structures for these conformers are compared to electronic structure theory calculations.