Low Temperature Physics: 29, 784 (2003); https://doi.org/10.1063/1.1614192 (4 pages)
Физика Низких Температур: Том 29, Выпуск 9-10 (Сентябрь 2003), c. 1036-1040    ( к оглавлению , назад )

Properties of solid hydrogen doped by heavy atomic and molecular impurities

N.N. Galtsov, A.I. Prokhvatilov, G.N. Shcherbakov, and M.A. Strzhemechny

B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, 47 Lenin Ave., Kharkov 61103, Ukraine
E-mail: galtsov@ilt.kharkov.ua


Using powder x-ray diffraction we studied the structural characteristics of normal and para hydrogen crystals doped with Ar, Kr, N2, and O2 impurities over the range from 5 K to the melting point of the hydrogen matrix. It has been established that in spite of very low solubility of the dopants in solid hydrogen, these impurities appreciably affect the structural characteristics. In particular, only nitrogen impurities do not change the molar volume of the matrix, the other three make the matrix expand. The Ar and Kr impurities also change the c/a ratio of the hcp matrix. The fact that both Ar and O2 have smaller molar volumes than hydrogen may be treated as evidence that these impurities form van der Waals complexes with the hydrogen lattice environment.

67.80.Mg - Defects, impurities, and diffusion
67.90.+z - Other topics in quantum fluids and solids; liquid and solid helium (restricted to new topics in section 67)