Thermo-optic characterization and numerical modeling of acetone and acetonitrile by laser-induced thermal lens spectroscopy
摘要
Laser-induced thermal lens spectroscopy was employed to measure the thermal diffusivity (D) and thermal conductivity (k) of acetone and acetonitrile at 298 K. A dual-beam configuration with a Nd:YAG excitation laser (532 nm, 95 mJ) and a He–Ne probe laser (632.9 nm, 5 mW) was used. At 298 K, D = 0.94 × 10−7 m2 s−1 and k = 0.195 W m−1 K−1 for acetone, and D = 0.114 × 10−7 m2 s−1 and k = 0.183 W m−1 K−1 for acetonitrile; all values agree with literature within 3%. Temperature-dependent measurements (288–328 K) reveal increases of ~ 15–22% in D and ~ 10% in k, consistent with enhanced molecular mobility at higher temperatures. A COMSOL Multiphysics model that incorporates finite cell geometry and realistic boundary conditions reproduces the experimental signals and predicts the thermal parameters within 4% without external calibration, establishing simulation as a predictive metrological tool. This integrated experimental–numerical framework provides reliable and reproducible thermo-optical characterization of volatile transparent liquids.