Abstract

Fitting experimentally measured Raman bands with theoretical model profiles is the basic operation for numerical determination of Raman peak parameters. In order to investigate the effects of peak modeling using various algorithms on peak fitting results, the representative Raman bands of mineral crystals, glass, fluids as well as the emission lines from a fluorescent lamp, some of which were measured under ambient light whereas others under elevated pressure and temperature conditions, were fitted using Gaussian, Lorentzian, Gaussian–Lorentzian, Voigtian, Pearson type IV, and beta profiles. From the fitting results of the Raman bands investigated in this study, the fitted peak position, intensity, area and full width at half-maximum (FWHM) values of the measured Raman bands can vary significantly depending upon which peak profile function is used in the fitting, and the most appropriate fitting profile should be selected depending upon the nature of the Raman bands. Specifically, the symmetric Raman bands of mineral crystals and non-aqueous fluids are best fit using Gaussian–Lorentzian or Voigtian profiles, whereas the asymmetric Raman bands are best fit using Pearson type IV profiles. The asymmetric O–H stretching vibrations of H₂O and the Raman bands of soda–lime glass are best fit using several Gaussian profiles, whereas the emission lines from a florescent light are best fit using beta profiles. Multiple peaks that are not clearly separated can be fit simultaneously, provided the residuals in the fitting of one peak will not affect the fitting of the remaining peaks to a significant degree. Once the resolution of the Raman spectrometer has been properly accounted for, our findings show that the precision in peak position and intensity can be improved significantly by fitting the measured Raman peaks with appropriate profiles. Nevertheless, significant errors in peak position and intensity were still observed in the results from fitting of weak and wide Raman bands having unnormalized intensity/FWHM ratios lower than 200 counts/cm⁻¹.

© 2017 The Author(s)

Compact remote Raman system and its applications under strong sunlight research

Zhicong Li, Bin Xue, Yiyi Zhao, Shuaidong Huang, Yiheng Liu, Zongcheng Ling, and Jianfeng Yang
Opt. Continuum 2(8) 1772-1781 (2023)

Fiber Raman background study and its application in setting up optical fiber Raman probes

Jiaying May and Ying-Sing Li
Appl. Opt. 35(15) 2527-2533 (1996)

Time-domain fit for improved contrast in quantitative coherent anti-Stokes Raman spectroscopy

Minjian Lu, Yujia Zhang, Jiarui Li, Yan Li, and Haoyun Wei
Opt. Express 31(16) 25571-25584 (2023)

Automated decomposition algorithm for Raman spectra based on a Voigt line profile model

Yunliang Chen and Liankui Dai
Appl. Opt. 55(15) 4085-4094 (2016)

Mie scattering interferometer and its application to the study of Raman scattering from molecules at a mercury interface

Azriel Z. Genack, King P. Leung, Harry W. Deckman, Premala Chandra, and Joel I. Gersten
Appl. Opt. 23(23) 4410-4421 (1984)