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-Tbrner spectrometer. The temperature of probe volume was determined by the fitting of N-2 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 v(1), v(3), and 2v(4) were reported. The relative intensity between v(1), v(3), and 2v(4) modes were also analyzed under different temperatures. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement