THE REACTIVITY OF HYDROGEN ATOMS IN THE LIQUID PHASE. III. THE REACTIONS WITH OLEFINS

1962 ◽  
Vol 66 (2) ◽  
pp. 291-295 ◽  
Author(s):  
T. J. Hardwick
Keyword(s):  
Liquid Phase ◽  
Phase Iii ◽  
Hydrogen Atoms

60Co γ-RADIOLYSIS OF HYDROGEN HALIDES AT 77 °K

1966 ◽  
Vol 44 (2) ◽  
pp. 191-197
Author(s):  
R. C. Rumfeldt ◽  
D. A. Armstrong
Keyword(s):  
Liquid Phase ◽  
Hydrogen Atom ◽  
Experimental Error ◽  
Dose Dependence ◽  
Solid Matrix ◽  
Reactive Intermediate ◽  
Hydrogen Atoms ◽  
Hydrogen Halides ◽  
Atoms And Molecules ◽  
The Difference

Yields of hydrogen formed in the 60Co γ-radiolyses of pure polycrystalline samples of HBr and HCl at 77 °K decrease with increasing dose in the range 0 to 1 × 1018 eV per g. The true initial yields are G(H2)solidHClat77°K = 6.3 ± 0.2 and G(H2)solidHBrat77°K = 12.3 ± 0.3. Within experimental error these are the same as the respective liquid-phase yields at −79 °C. For doses in excess of 2 × 1018 eV per g the dose dependence is no longer significant and the yields tend toward plateau values of 3.2 ± 0.1 and 10.3 ± 0.1 for HCl and HBr respectively. The dose dependence of the hydrogen yields is attributed to the scavenging of a reactive intermediate by the halogen atoms and molecules which accumulate in the solid matrix as the dose increases.In independent experiments with an apparatus of the Klein–Scheer type it was shown that hydrogen atoms react readily with films of HBr at 77 °K. There is, however, no evidence of a significant reaction with HCl at this temperature. The difference in behavior of the two hydrogen halides may be explained by their different activation energies for reaction with hydrogen atoms. The results of the γ-radiolyses are discussed in the light of these experiments and it is suggested that the dose dependence may be a result of the scavenging of an ionic intermediate rather than a thermal hydrogen atom.

The temperature dependence of bismuth structures under high pressure

2021 ◽  
Author(s):  
Xiaobing Fan ◽  
Shikai Xiang ◽  
Lingcang Cai
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Liquid Phase ◽  
Temperature Dependence ◽  
Electronic Structures ◽  
Phase Iii ◽  
Liquid Phase Transition ◽  
X Ray ◽  
First Order ◽  
X Ray Absorption

Abstract It is unclear whether there is a liquid-liquid phase transition or not in the bismuth melt at high temperature and high pressure, if so, it is necessary to confirm the boundary of the liquid-liquid phase transition and clarify whether it is a first-order phase transition. Here based on X-ray absorption spectra and simulations, the temperature dependence of bismuth structures has been investigated under different pressures. According to the similarity of characteristic peaks of X-ray absorption near edge structure (XANES) spectra, we have estimated that the possible temperature ranges of liquid-liquid phase transition are 779 K ~ 799 K at 2.74 GPa and 859 K ~ 879 K at 2.78 GPa, 809 K ~ 819 K at 3.38 GPa and 829 K ~ 839 K at 3.39 GPa and 729 K ~ 739 K at 4.78 GPa, respectively. Using ab initio molecular dynamics (AIMD) simulations, we have obtained the stable structures of the bismuth melt at different temperatures and pressures and calculated their electronic structures. Meanwhile, two stable phases (phase III-like and phase IV-like) of bismuth melts are obtained from different initial phases of bismuth solids (phase III and phase IV) under the same condition (3.20 GPa and 800 K). Assuming that the bismuth melt undergoes a phase transition from IV-like to III-like between 809 K and 819 K at 3.38 GPa, the calculated electronic structures are consistent with XANES spectra, which provides a possible explanation for the first-order liquid-liquid phase transition.

Structures and Solid-Liquid Phase Transition of High-Density Hydrogen Confined in Single-Walled Carbon Nanotubes

2009 ◽  
Vol 79-82 ◽  
pp. 67-70 ◽  
Author(s):  
Yue Yuan Xia ◽  
Ming Wen Zhao ◽  
Xiang Dong Liu ◽  
Yan Ju Ji
Keyword(s):  
Phase Transition ◽  
Carbon Nanotubes ◽  
Liquid Phase ◽  
Density Functional ◽  
Single Walled Carbon Nanotubes ◽  
Hydrogen Atoms ◽  
Liquid Phase Transition ◽  
Single Walled Carbon ◽  
Solid Liquid ◽  
Walled Carbon Nanotubes

Hydrogen with ultrahigh density confined in single-walled carbon nanotubes (SWCNTs) was investigated using density functional theory (DFT) and first principles molecular dynamics simulations (MDSs). Hydrogen atoms injected in to the cages of the SWCNTs via atomic collisions gradually form solid H2 molecular lattice with a characteristic of spiral multi-strands structure. The concentration of H2 confined in the SWCNTs can be as high as ~ 1.77×1023H2 /cm3, and the pressure between the H2 lattice and the wall of the SWCNT can be as high as ~ 77 GPa. When the system was heated to temperature higher than 700K, a solid-liquid phase transition was observed. When temperature rose to 1000K, a few H2 molecules dissociated forming a mixed liquid of H atoms, H2 molecules, and hydrogen trimers. Electron states near the Fermi level were appeared, which were attributed to the H atoms and the trimers. The electronic properties of the quasi-one-dimensional hydrogen confined in the SWNTs were thus substantially changed.

THE REACTIVITY OF HYDROGEN ATOMS IN THE LIQUID PHASE

1961 ◽  
Vol 65 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Thomas J. Hardwick
Keyword(s):  
Liquid Phase ◽  
Hydrogen Atoms
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