| 1. |
- Pritchard, R E, et al.
(författare)
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Bonding of H-CAs pairs in AlxGa1-xAs alloys
- 1994
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 50:15, s. 10628-10636
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Tidskriftsartikel (refereegranskat)abstract
- The local structure of CAs acceptors in AlxGa1-xAs has been investigated by studying the nondegenerate localized vibrational modes of H-CAs pairs with A1 symmetry, rather than those of isolated CAs impurities. Infrared absorption and Raman scattering measurements have been made on AlxGa1-xAs: 12C epilayers that (a) had been exposed to a radio-frequency hydrogen (deuterium) plasma or (b) contained hydrogen incorporated during growth. Arguments are advanced that indicate that the H(D) atom should occupy a bond-centered site between CAs and Ga atoms rather than between CAs and Al atoms at low temperatures. An ab initio local-density-functional calculation indicates that the energy is then lowered by 0.24 eV. This analysis has led to the assignment of five antisymmetric stretch modes and five symmetric (X) modes to H-CAs pairs at sites where the carbon atom that was originally unpaired had zero, one, two, three, or four Al nearest neighbors
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| 2. |
- BERTOLOTTO, L, et al.
(författare)
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RESULTS FROM (P)OVER-BAR-P-]PHI-PHI
- 1994
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Ingår i: NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA A-NUCLEI PARTICLES AND FIELDS. - : EDITRICE COMPOSITORI BOLOGNA. ; , s. 2329-2337
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Konferensbidrag (refereegranskat)abstract
- The reaction ($) over bar pp --> phi phi is investigated in the JETSET (PS202) experiment using an internal target in LEAR. Data have been analysed at a variety of beam momenta from 1.2 GeV/c to 2.0 GeV/c, corresponding to centre-of-mass energies between
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| 3. |
- I. Sinning, G.J. Kleywegt, S.W. Cowan, P. Reinemer, H.W. Dirr, R. Huber, G.L. Gilliland, R.N. Armstrong, X. Ji, P.G. Board, B. Olin, B. Mannervik & T.A. Jones
(författare)
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Structure determination and refinement of human alpha class glutathione transferase A1-1, and a comparison with the mu and pi class enzymes
- 1993
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Ingår i: Journal of Molecular Biology. ; 232, s. 192-212
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Tidskriftsartikel (refereegranskat)
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| 4. |
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| 5. |
- Purton, J., et al.
(författare)
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LDF pseudopotential calculations of the α-quartz structure and hydrogarnet defect
- 1992
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Ingår i: Physics and chemistry of minerals. - 0342-1791 .- 1432-2021. ; 18:6, s. 389-392
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Tidskriftsartikel (refereegranskat)abstract
- Ab initio LDF theory has been used to study the structure of the hydrogarnet defect in α-quartz. The predicted structure is in good agreement with the available sexperimental data. The techniques employed also yield a good model for the structure of α-quartz, giving an average Si-O bond length of 1.62 Å and average Si-O-Si angle of 142°.
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| 6. |
- Sinning, I, et al.
(författare)
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Structure determination and refinement of human alpha class glutathione transferase A1-1, and a comparison with the Mu and Pi class enzymes.
- 1993
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Ingår i: J Mol Biol. - 0022-2836. ; 232:1, s. 192-212
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Tidskriftsartikel (refereegranskat)abstract
- The crystal structure of human alpha class glutathione transferase A1-1 has been determined and refined to a resolution of 2.6 A. There are two copies of the dimeric enzyme in the asymmetric unit. Each monomer is built from two domains. A bound inhibitor, S-benzyl-glutathione, is primarily associated with one of these domains via a network of hydrogen bonds and salt-links. In particular, the sulphur atom of the inhibitor forms a hydrogen bond to the hydroxyl group of Tyr9 and the guanido group of Arg15. The benzyl group of the inhibitor is completely buried in a hydrophobic pocket. The structure shows an overall similarity to the mu and pi class enzymes particularly in the glutathione-binding domain". The main difference concerns the extended C terminus of the alpha class enzyme which forms an extra alpha-helix that blocks one entrance to the active site and makes up part of the substrate binding site.
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| 7. |
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| 8. |
- Estreicher, S.K., et al.
(författare)
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Stable and metastable states of C60H: buckminsterfullerene monohydride
- 1992
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Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 196:3-4, s. 311-316
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Tidskriftsartikel (refereegranskat)abstract
- Approximate ab initio Hartree-Fock and first-principles density functional calculations of potential energy surfaces and electronic structures of C60H show that the stable state has H attached to one C atom, outside the buckyball. This C atom is displaced radially outward and is close to being sp3 hybridized. The unpaired electron of C60H is delocalized. The calculated Fermi contact density at the proton is in good agreement with recent low-temperature μSR data. A metastable configuration has atomic H at the center of the ball (H@C60). Once trapped there, H must overcome a large barrier to go through the surface of C60. Other configurations we considered include H attached to one C atom but inside the buckyball, and H bridging one of the two inequivalent CC bonds. The barrier for diffusion of H from outside to the center of C60 have also been calculated. The results are compared to recent muon spin rotation studies in solid C60 and to the states of hydrogen in other forms of carbon.
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| 9. |
- Holbech, J. D., et al.
(författare)
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H2* defect in crystalline silicon
- 1993
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 71:6, s. 875-878
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Tidskriftsartikel (refereegranskat)abstract
- Detailed infrared studies have been carried out on proton- and deuteron-implanted Si. A dominant trigonal defect involving a pair of inequivalent hydrogen atoms has been identified, with local modes at 2061.5, 1838.3, 1599.1, and 817.2 cm-1. The structure, the local modes, and the isotopic shifts of the H2* defect have been calculated using ab initio pseudopotential cluster theory. The structure is consistent with channeling and uniaxial stress experiments. The calculated frequencies and isotopic shifts are in close agreement with those observed.
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| 10. |
- Jones IV, David R, et al.
(författare)
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The asphalt model : Results of the SHRP asphalt research program
- 1991
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Ingår i: Proceedings of Strategic Highway Research Program and Traffic Safety on Two Continents. Conference in Gothenburg, Sweden, September 18-20, 1991. - Linköping : Statens väg- och transportforskningsinstitut. ; , s. 1-13
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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