Temperature dependent Raman spectra of ammonia ranging from 3150 cm⁻¹ to 3810 cm⁻¹ for combustion applications

Abstract

Applying in combustion research, Raman scattering technique can provide high accuracy and high precision measurements of temperature and major species concentrations. However detailed knowledge of the temperature dependent Raman spectra of the probed species is a precondition to realise the potential of high precision and accuracy of the technique. As a carbon free novel fuel, the knowledge of high temperature Raman spectra of ammonia is rarely reported. We measured the Raman spectra of ammonia ranging from 299 K to 760 K. The high resolution Raman spectra are excited with a continuous wave 532 nm laser and detected with an low aberration Schmidt-Czerny-Turner spectrometer. The temperature of probe volume was determined by the fitting of N2 Raman spectra. The Raman spectra of ammonia under different temperatures were quantitatively normalized to the same number density to research the temperature behavior of spectra. Within the Raman shift region from 3150 cm−1 to 3810 cm−1, the Raman intensity and the polarization anisotropy of vibrational modes ν1, ν3, and 2ν4 were reported. The relative intensity between ν1, ν3, and 2ν4 modes were also analyzed under different temperatures.

Pressure dependence in aqueous-based electrochemical CO2 reduction

“…We built a Raman system employing an 18 W continuous-wave laser as the excitation source to realize a >300 mm working distance (Supplementary Fig. 9 ) 44 . This setup enhanced the signal-to-noise ratio compared to conventional ones: the incident laser beam was highly focused and transmitted along the cathode surface, and the scattered Raman signals were collected, collimated, and screened in the perpendicular direction (Fig.…”

Pressure dependence in aqueous-based electrochemical CO2 reduction

“…W continuous-wave laser as the excitation source to realize a > 300 mm working distance (Supplementary Fig. 9) 33 . This setup also greatly enhanced the signal-to-noise ratio compared to conventional ones: The incident laser beam was highly focused and transmitted along the cathode surface, and the scattered Raman signals were collected, collimated, and screened in the perpendicular direction (Fig.…”

Quantitative in-situ Raman spectroscopy for gas and liquid phase catalytic reactions

“…Fig. 1 shows experiment set-up for the near-surface in-situ Raman spectroscopy, which is similar to the system reported before [4]. A narrow-band continuous wave laser (Coherent, Inc. Verdi G18) with maximum 18 W output at 532 nm provided the Raman excitation source.…”