A search accelerated correct intensity Fourier transform microwave spectrometer with pulsed laser ablation source

Abstract

The ablation of metal surfaces in the presence of a precursor gas produces reaction products which are often difficult to predict and highly dependent on ablation conditions. This article describes the successful development and implementation of a laser ablation source-equipped Fourier transform microwave spectrometer capable of observing 4 GHz regions of spectra in a single data acquisition event. The dramatically increased speed with which regions may be searched, when compared to other high resolution microwave techniques, allows the source conditions to be the prime variable in laser ablation microwave spectroscopic studies. A second feature of the technique is that observed spectral features have correct relative intensities. This is advantageous when assigning observed spectra. The study of two metal chlorides, AgCl and AuCl, illustrate the instrument's benefits.

Rapid probe of the nicotine spectra by high-resolution rotational spectroscopy

“…23 In that work the authors provided the rotational constants of two conformers obtained from a fit of the estimated line centers. In the present work, which was also previously presented as a communication to the same conference in its 65th edition, 24 we have analyzed the rotational spectra of nicotine using a new design of a linear fast passage (chirp) FTMW spectrometer [25][26][27] called IMPACT complemented with the established setup of a short stimulus (pulse) excitation FTMW spectrometer of the COBRA type. This new approach provides instant broadband performance using fast linear frequency sweeps (chirps), instead of on/off-modulated CW radiation (pulses), to polarize the sample.…”

The gas phase characterization of perfluorobutyryl chloride, C3F7COCl, using chirped pulse Fourier transform microwave spectroscopy

“…Rotational spectra were recorded using a chirped pulse Fourier transform microwave (CP-FTMW) spectrometer located at the University of North Texas. This instrument has been described in detail elsewhere [10]. The inspiration for this technique came from Ref.…”

A direct digital synthesis chirped pulse Fourier transform microwave spectrometer

“…8 The signal-to-noise of the instrument in both the DDS and AWG configurations is lower than the original Pate lab spectrometer, 8 due to the polarization power available (50 W versus 2 kW), but comparable to other low power (<100 W) CP-FTMW spectrometers. 9,11,13,23,25 …”

“…8 The bandwidth, acquisition speed, sensitivity, and relative intensity information attainable with the chirped pulse design has led to its increasingly widespread use in the molecular spectroscopy community. [9][10][11][12][13][14][15][16] There are three major components of CP-FTMW spectrometers that enable the collection of broadband spectra: high sample rate digitizers for acquisition of the microwave emission, broadband high power amplifiers (based on either solid state or traveling wave tube technology) to ensure sufficient power for sample polarization, and Arbitrary Waveform Generators (AWGs) or Arbitrary Function Generators (AFGs) for producing the chirped polarization pulse. In state-of-the-art, multi-GHz bandwidth instruments each of these major components require significant power and physical space.…”