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Refractive index and polarizability of polystyrene under shock compression
- Zhang, Xuping, Wang, Guiji, Luo, Binqiang, Tan, Fuli, Bland, SimonN., Zhao, Jianheng, Sun, Chengwei, Liu, Cangli
- Journal of materials science 2018 v.53 no.17 pp. 12628-12640
- equations, polystyrenes, refractive index, semiconductors, temperature, thermodynamics
- The refractive index, polarizability and thermodynamic response of polystyrene under shock compression were investigated through experiments and theoretical analysis, and a relationship between the refractive index and the density, pressure and temperature of the polystyrene was obtained. Above a pressure of 20 GPa, an obvious inflexion was observed in how the refractive index of the polystyrene varied with the thermodynamic variables; in particular, it was found to depend strongly on the temperature (as obtained using a semiempirical complete equation of state). Relating the measured refractive index to the polarizability indicates that the polarizability decreased from 1.28 × 10⁻²³ cm³ at ambient conditions, to 0.98 × 10⁻²³ cm³ at pressure of 33 GPa, indicating that the lowest direct band gap [Formula: see text] of polystyrene becomes < 2 eV, similar to that of many semiconductor materials.