^{1}Key Laboratory of Thermal Fluid Science and Engineering of MOE, Xi'an Jiaotong University, P.R. China

**Keywords:** ab initio potential; kinetic theory**property:** transport properties**material:** hydrogen, deuterium and their binary mixtures

Ab initio potential, determined from quantum mechanical calculations, was able to produce highly accurate transport properties of monatomic gases, such as helium, neon and argon. The calculated values of transport property were needed in metrology and the calibration of measuring instruments. For hydrogen, potential by ab initio calculations could be used to obtain its transport properties, which played an important role in the design and operation of many processes of the hydrogen energy system. However, it is difficult to determine potential energy surface of diatomic molecules by first-principles calculations due to the larger size of the basis set and lower symmetry of the system. Recently, a four-dimensional interaction potential was developed in ab initio calculations for two ground-state hydrogen molecules by Patkowski et al. [J. Chem. Phys. 129, 094304 (2008)], with an order of magnitude more accurate than previously available potentials. From the new intermolecular potential, viscosity coefficient and thermal conductivity coefficient of hydrogen were studied by Mehl and his co-workers [Int. J. Thermophys. 31, 740 (2010)]. In present work, the spherically symmetric representation of ab initio potential, obtained by Patkowski et al., was used to predict transport properties of pure H2, pure D2 and binary mixtures H2-D2 at low-density in temperature ranges of 100 K to 5000 K, including viscosity coefficient, thermal conductivity coefficient, thermal diffusion coefficient and thermal diffusion factor. Close agreements were found between present results and that of literature data. It was shown that isotropic version of high-quality potential presented by Patkowski et al. was effective in predicting accurate transport properties for hydrogen, deuterium and their binary mixtures. The theoretically calculated values could provide useful supplements to experimental results of hydrogen, deuterium and their binary mixtures. This work has been supported by the National Natural Science Foundation of China (Grant 51006083; 50836004) and the Fundamental Research Funds for the Central Universities.

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