Calculation of Symmetric Stretching Frequency in Molten BeF2by Molecular Dynamics Method

The molecular dynamics method was applied to molten BeF2, in which the pair potentials of the Born-Mayer-Huggins type were employed. The Fourier transform of the distances between a Be2+ ion and its nearest neighboring F− ions averaged over total 12 Be2+ ions gave the frequency of about 175 cm−1 as the symmetric stretching frequency which is in satisfactory agreement with 282 cm−1 obtained with Raman spectroscopy. The self-diffusion coefficients of Be2+ and F− ions were estimated to be 2×l0−10m2/sec and the internal energy was −2,559 kJ/mol at 973 K.