Studying the Influence of T2O Substitution for H2O on the Dynamic Properties, Density Maximum, and Melting Point of Ice in Terms of the Lattice Dynamics Method

An isotopic effect arising from the substitution of superheavy water molecules for normal water molecules in ice (I-h) has been studied by the lattice dynamics method in a quasi-harmonic approximation using a rigid three-point potential modified to reproduce the superheavy water properties. It has been shown that the considerable variation of the vibrational state density upon substituting 12.5, 50, and 100% of water molecules takes place only in the range of libration. The temperature dependence of the superheavy ice density has been calculated, and the density maximum for this ice near 60 K has been predicted. A relationship between the melting point of (T2O + H2O)-ice I-h and the T2O molecule concentration in its structure has been constructed, and this relationship has been found to be linear.

Automated summary

The isotopic effect of substituting superheavy water molecules for normal water molecules in ice (I-h) was investigated using the lattice dynamics method. The results showed that significant changes in the vibrational state density occurred only in the libration range when 12.5%, 50%, and 100% of water molecules were substituted. The temperature dependence of superheavy ice density was calculated, and a maximum density near 60 K was predicted. A linear relationship between the melting point of (T2O + H2O)-ice I-h and the T2O molecule concentration was observed.