Determination of the absolute Raman cross-sections of α-S8 film at ultralow frequencies pumped by 488 and 785 nm lasers

Absolute Raman cross-sections are widely used for quantitative analyses of condensed phases. However, solid thin films showing ultralow frequency (ULF) Raman characteristics at <100 cm(-1) have not been studied deeply. Herein, we demonstrate an ULF Raman spectrometer equipped with 488 and 785 nm pumped lasers and determine the absolute Raman cross-sections of 34-mu m-thick alpha-S-8 film, which presents Raman peaks at approximately 27, 50, 83, 154, and 220 cm(-1). These experimentally measured ultralow Raman frequencies and Raman cross-sections were also confirmed via first principles density functional theory. Thus, our Raman cross-section studies can be utilized as a quantitative standard for thin films showing ULF Raman characteristics.

Automated summary

Absolute Raman cross-sections are important for quantitative analyses of condensed phases. This study focuses on solid thin films with ultralow frequency Raman characteristics. A ULF Raman spectrometer is used to determine the absolute Raman cross-sections of an alpha-S-8 film and these measurements are confirmed using density functional theory. The results can be used as a quantitative standard for thin films with ULF Raman characteristics.