Temperature dependence of CO₂ densimetry using micro-Raman Spectrometry at laboratory conditions

The CO₂ densimetry based on CO₂ Fermi diad (delta, cm^–1) is a powerful method for estimating the depth of a rock’s origin. To enhance the accuracy of delta, we investigated both room and sample temperature dependency under laboratory conditions. We examined sample temperature dependence of delta while raising sample temperature using a heating-cooling stage at a constant room temperature. The results showed no sample temperature effect at least at temperatures of 21–26∞C. Similarly, in order to evaluate room temperature effect, we measured delta while raising room temperature by an air conditioner at constant sample temperature. Independent fluctuation of room and sample temperatures showed that changes in room temperature and the Raman system, not the influence of sample temperature, affect delta. In order to enhance the accuracy, we suggested a new correction formula for CO₂ Fermi diad, which functions to correct for the influence of the temperature effects.