Deuteration-induced structural phase transition versus quantum paraelectric behavior: Quantum chemical modeling of H/D bonded materials

摘要

On the examples of the K-3(H/D)(SO4)(2) family (I), the derivatives of 9-hydroxyphenalenone (II) and chromous acids alpha-(H/D)CrO2 (III) the problem of the deuteration-induced structural phase transition (SPT) is considered using pseudospin dynamic Ising model formalism. The pseudospin Hamiltonian parameters-tunneling integrals Omega(HID) and Ising model coupling parameters J(ij)(H/D) along with molecular field parameters J(0)(H/D) have been evaluated on the base of quantum chemical models and various computational techniques. The crystal-chemistry factors that influence on the values of these parameters are discussed. For I and II solids zero-dimensional character of the H-bond network is believed to be the main reason of the deuteration-induced SPT, although the pronounced geometrical (H/D) isotope effect (0.04 angstrom) also may play a noticeable role for I. Meanwhile for III such SPT is due to the giant (0.1 angstrom) geometrical (H/D) isotope effect.