Rotational spectrum of three conformers of 3,3-difluoropentane: Construction of a 480MHz bandwidth chirped-pulse Fourier-transform microwave spectrometer

Reduced bandwidth chirped-pulse microwave spectroscopy for analysis of weakly bound dimers: Rotational spectrum and structural analysis of CH2ClF⋯FHCCH2

“…Recent development of a reduced (480 MHz) bandwidth chirped-pulse Fourier-transform microwave spectrometer (CP-FTMW) at EIU [34] has greatly facilitated searching for spectra of weakly bound complexes. This instrument has been used to successfully identify numerous conformers [34] and also has been proven effective in finding dimers [5,7].…”

A direct digital synthesis chirped pulse Fourier transform microwave spectrometer

“…A common-mode rejection design (Figure 1) was employed to minimize LO phase jitter by splitting (Minicircuits ZX10-2-183-S+) the doubled PLL output to drive both the upconversion and downconversion mixers (as done in previous CP-FTMW circuits 9 ). To evaluate the phase stability of the instrument 10 million FIDs from the 3 21 -3 12 AA transition in acetone (10762.6 MHz rest frequency, measured with 11 900 MHz LO) were averaged with the DDS/PLL setup and with a conventional AWG/synthesizer circuit (Figure 4).…”

“…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.…”

Determination of nuclear spin–rotation coupling constants in CF3I by chirped-pulse Fourier-transform microwave spectroscopy

“…New methods are being developed to apply CP-FTMW to the study of conformational isomerisation in biomolecules [6]. Very recently, a new version of the CP-FTMW spectrometer has been developed at a significantly reduced cost [7]. The many opportunities presented by this emergent technique have motivated the construction of a CP-FTMW spectrometer covering a frequency band between seven and eighteen gigahertz within our group.…”