Thermal expansion of α-nitrogen ice in terahertz spectroscopy

摘要： The volumetric thermal expansion coef?cient of a-nitrogen (N2) ice is calculated for temperatures between 10 and 25 K using its terahertz transmission data and a phonon model. The observed dip in terahertz transmission around 1.45 THz is modeled as phonon absorption based on an intermolecular potential which is sum of the Lennard-Jones potential and quadrupole–quadrupole interaction term. Using this model and our experimental data, the lattice parameters of a-N2 ice were obtained.