Pulsed molecular beam microwave

III Pulsed Molecular Beam, Fourier Transform Microwave Spectroscopy 89... 

R. D. Suenram, J. U. Grabow, A. Zuban, I. Leonov, A portable, pulsed-molecular-beam, Fourier-transform microwave spectrometer designed for chemical analysis. Rev. Sci. Instrum., 70(4), 2127-2135 (1999). 

Figure 15. The pulsed molecular beam spectrometer used to record the microwave spectrum of CaNC [108] and CaOH [24], [Reprinted from ref. 108, Copyright 1994 American Institute of Physics.]...

Only the most stable confomer gauche) was observed in the pulsed molecular beam Fourier transform microwave spectrum. 

Only the most stable eonformer (gauche-anti-gauche") was observed in the pulsed molecular beam Fourier transform microwave spectmm. The eonformer is stabilized by an intramolecular N-H -tc hydrogen-bonding interaction. 

From Suenram RG, Grabow J, Zuban A, and Leonov I (1999) A portable pulsed-molecular-beam Fourier-transform microwave spectrometer designed for chemical analysis. Review of Scientific Instruments 70 2127-2135. 

An alternative approach to obtaining microwave spectroscopy is Fourier transfonn microwave (FTMW) spectroscopy in a molecular beam [10], This may be considered as the microwave analogue of Fourier transfonn NMR spectroscopy. The molecular beam passes into a Fabry-Perot cavity, where it is subjected to a short microwave pulse (of a few milliseconds duration). This creates a macroscopic polarization of the molecules. After the microwave pulse, the time-domain signal due to coherent emission by the polarized molecules is detected and Fourier transfonned to obtain the microwave spectmm. 

The first stage was the production of a pulsed free-jet molecular beam of helium containing 20% CO, which was then crossed with an electron beam to produce ionisation. The ions were produced close enough to the beam nozzle for cooling to occur downstream. Some 4 cm from the nozzle the beam entered a confocal Fabry-Perot cavity where it was exposed to millimetre wave radiation close to 120 GHz in frequency. Following microwave excitation, when on resonance, the beam was probed with a Nd YAG pumped dye laser beam with the frequency chosen to drive rovibronic components of the A 2 U-X 2 + band system. Figure 11.54 shows two recordings of a spin component of the lowest rotational transition the line shown in (a) is... 

Blanco S, Sanz ME, Mata S et al (2003) Molecular beam pulsed-dischtirge Fourier transform microwave spectra of CH3—C=C—F, CH3—(C=C)2 F, and CH3—(C=C)3—F. Chem Phys Lett 375 355-363... 

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