Millimeter wave spectroscopy

No data have been presented to date on the utility of far-infrared or millimeter-wave spectroscopy for other peroxy radicals or on its possible use in the troposphere when combined with a low-pressure absorption cell. 

The detection of the r-BuOH trapping product 703 and of the dimer 746 gives further evidence for the intermediacy of 744 and 745, respectively. Silanimine 735 is an intermediate in the synthesis of silaisocyanide 737 by retro-ene reaction from 747 under FVT conditions (equation 246)333. 737 was characterized by millimeter wave spectroscopy. 

The detection and identification of molecules in interstellar space is possible by millimeter wave spectroscopy. The independent synthesis and detection of such reactive species, e.g. by flash vaccuum thermolysis and mm wave spectroscopy, provides proof for their cosmochemical existence. The detection of the J 6 —> 7 rotational transition in the decomposition products of t-Bu2HSi—NH(CH2— C=CH) indicated the formation of HNSi (Table 20)333. 

A detailed experimental investigation of the THP-HzO complex (with molecular beam Fourier transform (FT) microwave spectroscopy, free-jet millimeter-wave spectroscopy, and ab inito calculations) revealed that the lowest energy species has the water in an axial position. <1998CEJ1974>. Similar studies into the TFIP-FICl complex allowed both the axial and equatorial hydrogen-bond complexes to be characterized it was not possible to unequivocally determine which of the two is more stable <1999AGE1772>. 

These discoveries could hardly have been brought about without the extensive knowledge of energy levels, selection rules, transition probabilities and spectra assembled by laboratory spectroscopy for a very wide range of molecules. Microwave spectroscopy in the centimeter- and millimeter-wave regions is a well-established research field for further information the reader is referred to the books by Gordy and Cook (1970), and Townes and Schawlow (1955), and to a recent review on millimeter-wave spectroscopy by Winnewisser et al. (1972). Reviews on interstellar molecules are given by Snyder (1972) and Rank etal. (1971). 

Trimethylenetetrazole gave as the main products nitrogen, ethylene, and poly-A-cyanoformimine. The monomer CH2=N—CN could be detected by direct introduction of the pyrolysis vapors into a mass spectrometer (Eq. 44)198 and has been fully identified by millimeter wave spectroscopy.1983... 

Millimeter wave spectroscopy with a free space cell such as a Broida oven is more sensitive than lower frequency microwave spectroscopy. However, the higher J transitions monitored by millimeter wave spectroscopy often do not show the effects of hyperfine structure. In the case of CaOH and SrOH, the proton hyperfine structure was measured in beautiful pump-probe microwave optical double resonance experiments in the Steimle group [24,68], They adapted the classic atomic beam magnetic resonance experiments to work with a pulsed laser vaporization source and replaced the microwave fields in the A and C regions by optical fields (Fig. 15). These sensitive, high-precision measurements yielded a very small value for the proton Fermi contact parameter (bF), consistent with ionic bonding and a... 

L. Genzel, F. Kremer, A. Poglitsch, and G. Bechtold, Relaxation Processes on a Picosecond Time Scale in Hemoglobin and Poly (l-Alanine) Observed by Millimeter-Wave Spectroscopy, Biopolymers 22, 1715-1729 (1983). 

Structural studies of higher energy conformers by millimeter-wave spectroscopy Oxalic acid ... 

AUen MD, Ziurys LM (1997) Millimeter-wave spectroscopy of FeF rotational analysis and bonding study. J Chem Phys 106 3494—3503... 

Latter WB, Radford SJE, JeweU PR, Mangum JG and Bally J (eds) (1997) CO Twenty Five Years of Millimeter Wave Spectroscopy. Dordrecht Kluwer. 

K., and Tanaka, T. (2004) Determination of the proton tunneling splitting of the vinyl radical in the ground state by millimeter-wave spectroscopy combined with supersonic jet expansion and ultraviolet photolysis. J. Chem. Phys., 120, 3604-3618. 

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