Hydrogen atom vibration anharmonism in ZrVsub(2)Hsub(1.78)

The temperature dependence of the line width in a spectrum of ZrV2sub(2)Hsub(1.78) optical vibrations is analyszed. It is established experimentally that the spectrum band width of ZrVsub(2)Hsub(1.78) optical lattice vibrations grows linearly with temperature within the 296-463 K temperature range. Insignificant increase of the spectrum mean energy optical phonons is observed with temperature increase. It is assumed that the third order anharmonism is the basic process limiting the lifetime of optical photnons in the investigated temperature range. As the boundary energy of the spectrum of ZrV2sub(2)Hsub(1.78) hydride acoustic lattice vibrations 2 Esub(ac)sup(bound) < Esub(opt), the fulfilment of the law of energy conservation demands the presence of some final width of a band of optical lattice vibrations