First-principles investigations of isotope effects in thermodynamic properties of TiX2 (X = H, D, and T) system

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	First-principles investigations of isotope effects in thermodynamic properties of TiX2 (X = H, D, and T) system
	C. H. Hu; D. M. Chen; Y. M. Wang; K. Yang
	2008
发表期刊	Journal of Alloys and Compounds
ISSN	0925-8388
卷号	450 期号:1-2 页码:369-374
摘要	As hydrogen, deuterium and tritium storage materials, a series of investigations of mechanical and thermal properties of titanium hydrides, deuterides and tritides have been performed, however, very limited theoretical studies of thermodynamic properties for them can be found. Based on density-functional theory (DFT) and density-functional perturbation theory (DFPT) we have discussed systematically the hydrogen isotope effects on the thermodynamic properties of TiX2 (X = H, D, and T) system. Our calculations indicate that for evaluating accurately their physical properties at absolute zero temperature, such as the equilibrium lattice constants, bulk modulus, and heat of formation, the zero-point energy correction must be taken into account. By performing the phonon calculation within quasiharmonic approximation (QHA), we obtain their vibrational free energies, vibrational entropies, and temperature dependence of specific heat, thermal expansion, and bulk modulus. Those results demonstrate that comparing with TiH2, TiT2 and TiD2 are more stable and the zero-point effects play an important role in their thermal expansion. The increase in the force constant between Ti and H causes the higher value of specific heat of TiH2 during the phase transition from FCC to FCT. In addition, comparing with available experimental values, we can conclude that QHA is feasible for describing the thermal properties of TiX2. (C) 2006 Elsevier B.V. All rights reserved.
部门归属	[wang, y. m.] chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china. [hu, c. h.; chen, d. m.; yang, k.] chinese acad sci, natl engn res ctr, shenyang 110016, peoples r china.;wang, ym (reprint author), chinese acad sci, inst met res, shenyang natl lab mat sci, 72 wenhua rd, shenyang 110016, peoples r china;ymwang@imr.ac.cn
关键词	Isotope Effects Thermodynamic Properties Density-functional Perturbation Theory Quasiharmonic Approximation Functional Perturbation-theory Neutron Spectroscopy Thermal-properties Titanium Hydrogen Dependence Expansion Constants Palladium Hydrides
URL	查看原文
WOS记录号	WOS:000252860900063
引用统计	被引频次：30[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/32818
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	C. H. Hu,D. M. Chen,Y. M. Wang,et al. First-principles investigations of isotope effects in thermodynamic properties of TiX2 (X = H, D, and T) system[J]. Journal of Alloys and Compounds,2008,450(1-2):369-374.
APA	C. H. Hu,D. M. Chen,Y. M. Wang,&K. Yang.(2008).First-principles investigations of isotope effects in thermodynamic properties of TiX2 (X = H, D, and T) system.Journal of Alloys and Compounds,450(1-2),369-374.
MLA	C. H. Hu,et al."First-principles investigations of isotope effects in thermodynamic properties of TiX2 (X = H, D, and T) system".Journal of Alloys and Compounds 450.1-2(2008):369-374.