Advancements in Raman Spectroscopy: Experimental Analysis of Molecular Vibrations under Controlled p-T Conditions

Abstract

Raman spectroscopy is a powerful vibrational technique used to study molecular structures, interactions and dynamics through inelastic scattering of photons. Despite being historically limited by low scattering efficiency and expensive instrumentation, recent advancements such as Surface Enhanced Raman Spectroscopy (SERS), Coherent Anti-Stokes Raman Spectroscopy (CARS) and Resonance Raman Spectroscopy (RRS) have broadened its applications in chemistry, biology and materials science. This study examines Raman spectra of various samples, including quartz, silicon wafers, calcite and aqueous phases containing CO₂ and CH₄, using a Horiba Jobin Yvon LabRAM HR800 Raman system. Controlled temperature and pressure conditions were achieved using a Bassett-type hydrothermal diamond anvil cell (HDAC). Analysis focused on spectral resolution, peak fitting, full width at half maximum (FWHM) and asymmetry to understand molecular responses under variable excitation sources (532 nm and 785 nm lasers) and grating densities. Results demonstrate clear variations in Raman spectral features with changes in experimental conditions, highlighting the technique’s sensitivity in probing molecular vibrations and interactions. The findings validate Raman spectroscopy as a versatile tool for characterizing solid, liquid and gaseous systems, particularly in high-pressure, high-temperature environments.