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The solid state reaction between AgI and HgI2
Vol. 40, No. 5
ABSTRACTS
OF ARTICLES TO BE PUBLISHED IN J. PHYS. CHEM. SOLIDS
with the evident distrrbutions between the prmcipal g values arising from an isotropic randomness at the titamum sites. However, the g parameter drstributrons of the hole resonance, and theu changes during the addition of TiOz indicate the development of Silicate structures in the glasses which are the precursors of the major low temperature crystalline phases The invanance of the hole and electron resonance lmes with pre-crystallrzatron heat treatments indicates that neither the titanium associated structures of the basic silicate structure of the glass are changed by such treatments. Recewed 23 December 1980 Revised 20 March 198 1 9
THE HOPPING MOTION OF THE SELFTRAPPED EXCITON IN NaCl
was investigated wrth X-rays. The sample used in the experrment showed a macroscopic hydrogen density mode, leading to a curvature of the whole crystal plate wrth the o-phase on the concave side and the cy’-phase on the convex side. In addition an o-phase wettmg layer was found on top of the or-phase separated from the bulk cur-phase by a mrxed (Y-Q’ phase regron. In a snnple model therr thickness was determmed to about - 1 0 and - 7.0 m, resp. This thm wetting layer leads to a new interpretation of the phase transitron of H and Nb, mvolvmg the fanuliar long-range elastic mteractron as well as a short-range surface free energy contrrbutron. Recerved 15 December 1980
11.
K. Tammura and N. Itoh, Department of Crystallme Materials Science, Faculty of Engmeermg, Nagoya University, Nagoya 464, Japan. The decay kmetrcs and the yield of the n luminescence from the lowest triplet state of the self-trapped exciton have been studied m NaCl contammg Lr+ ions. It 1s found that the n lummescence band which 1s observed at 6 K 1s replaced by a lummescence band peaked at 3.34 eV above 77 K. The 3.34 eV lummescence band is ascribed to the recombmatron of the relaxed excrton trapped by a Lr+ ion, (V,e),. The decay of the n lummescence induced by an electron pulse and the time change of the lummescence from are explamed in terms of the characterrstrc (vke)Ll equation of the diffusron-limited reaction of the lowest tripled self-trapped excrtons with the Li+ ions. From the analysis of the dependence of the decay rate of the 7r lummescence on temperature and on the Lt+ concentration, we found the drffusron constant D of the lowest tnpled self-trapped exciton in NaCl to be grven by D = D,,e-Ea’kT withD, = 2.13 x 10s3 cm* see-’ and E, = 0.13 eV. The present result can be regarded as the first clear experrmental evidence for the hoppmg drffusion of the self-trapped exciton in alkali halides. The obtamed values of E, and Do are discussed usmg the small polaron theory. The effect of the anharmomcrty on the hoppmg of the self-trapped excrtons 1s suggested to be srgnificant. Received 29 December 1980 10.
CRITICAL POINT WETTING IN NbH,.B, H. Zabel, B. Schonfeld and S.C. Moss, Physics Department, University of Houston, Houston, TX 77004, U.S.A.
The local o--o phase distrtbutron 111a thm Nb smgle crystal loaded with the crrtrcal H-concentratron
ui
THE SOLID STATE REACTION BETWEEN AgI AND Hg12 V Leute and B. Schroder, Institute of Physrcal Chemistry, University of Munster, Schlossplatz 4,440O Munster, Germany.
The kmetrcs of the solid state reaction between AgI and Hg12 1s mvestrgated experimentally by measurmg the thickness of the layer of the oz-Ag2Hg14 product phase as a function of the annealing tune and the reaction temperature. A theoretical expression 1s denved whrch allows the calculatron of the variation of the chemical potentials of the binary components across the product layer consrdermg the vanatron of the product phase composition A value of A0 = 6 KJ mole-’ 1s estimated for the standard affinity for the formation of storchrometrrc Ag, Hg14 from the binary components AgI and Hg12. Recewed 19 December 1980 Revised 20 March 198 1
12.
THE MAGNETIC BEI-IAVIOUR OF DILUTED CrAl ALLOYS I Pop, D. Dadlrlat, T. Petrrsor and A. Gmrgm, Department of Physrcs, Cluj-Napoca University, 3400 CluJ-Napoca, Romania
Magnetic susceptrbrhty as a function of temperature of binary CrAl alloys contammg 0.7, 1.07, 1 35, 1.59, 1.79, 1.98,2.18, 2.84,3.74 and 4.36 at.% Al 1s mvestigated. Alummmm, by alloymg, acts on the Neel temperature of pure chrommm gwmg rrse to a complicated phase diagram The behavrour of the magnetic susceptrbility as a function of temperature, m the ordered phase, for the samples contammg 1 28,2.18 and 2.84 at.% Al 1s found to be temperature independent. In the paramagnetrc region, for the samples contaimng between 1.07
ABSTRACTS
OF ARTICLES TO BE PUBLISHED IN J. PHYS. CHEM. SOLIDS
with the evident distrrbutions between the prmcipal g values arising from an isotropic randomness at the titamum sites. However, the g parameter drstributrons of the hole resonance, and theu changes during the addition of TiOz indicate the development of Silicate structures in the glasses which are the precursors of the major low temperature crystalline phases The invanance of the hole and electron resonance lmes with pre-crystallrzatron heat treatments indicates that neither the titanium associated structures of the basic silicate structure of the glass are changed by such treatments. Recewed 23 December 1980 Revised 20 March 198 1 9
THE HOPPING MOTION OF THE SELFTRAPPED EXCITON IN NaCl
was investigated wrth X-rays. The sample used in the experrment showed a macroscopic hydrogen density mode, leading to a curvature of the whole crystal plate wrth the o-phase on the concave side and the cy’-phase on the convex side. In addition an o-phase wettmg layer was found on top of the or-phase separated from the bulk cur-phase by a mrxed (Y-Q’ phase regron. In a snnple model therr thickness was determmed to about - 1 0 and - 7.0 m, resp. This thm wetting layer leads to a new interpretation of the phase transitron of H and Nb, mvolvmg the fanuliar long-range elastic mteractron as well as a short-range surface free energy contrrbutron. Recerved 15 December 1980
11.
K. Tammura and N. Itoh, Department of Crystallme Materials Science, Faculty of Engmeermg, Nagoya University, Nagoya 464, Japan. The decay kmetrcs and the yield of the n luminescence from the lowest triplet state of the self-trapped exciton have been studied m NaCl contammg Lr+ ions. It 1s found that the n lummescence band which 1s observed at 6 K 1s replaced by a lummescence band peaked at 3.34 eV above 77 K. The 3.34 eV lummescence band is ascribed to the recombmatron of the relaxed excrton trapped by a Lr+ ion, (V,e),. The decay of the n lummescence induced by an electron pulse and the time change of the lummescence from are explamed in terms of the characterrstrc (vke)Ll equation of the diffusron-limited reaction of the lowest tripled self-trapped excrtons with the Li+ ions. From the analysis of the dependence of the decay rate of the 7r lummescence on temperature and on the Lt+ concentration, we found the drffusron constant D of the lowest tnpled self-trapped exciton in NaCl to be grven by D = D,,e-Ea’kT withD, = 2.13 x 10s3 cm* see-’ and E, = 0.13 eV. The present result can be regarded as the first clear experrmental evidence for the hoppmg drffusion of the self-trapped exciton in alkali halides. The obtamed values of E, and Do are discussed usmg the small polaron theory. The effect of the anharmomcrty on the hoppmg of the self-trapped excrtons 1s suggested to be srgnificant. Received 29 December 1980 10.
CRITICAL POINT WETTING IN NbH,.B, H. Zabel, B. Schonfeld and S.C. Moss, Physics Department, University of Houston, Houston, TX 77004, U.S.A.
The local o--o phase distrtbutron 111a thm Nb smgle crystal loaded with the crrtrcal H-concentratron
ui
THE SOLID STATE REACTION BETWEEN AgI AND Hg12 V Leute and B. Schroder, Institute of Physrcal Chemistry, University of Munster, Schlossplatz 4,440O Munster, Germany.
The kmetrcs of the solid state reaction between AgI and Hg12 1s mvestrgated experimentally by measurmg the thickness of the layer of the oz-Ag2Hg14 product phase as a function of the annealing tune and the reaction temperature. A theoretical expression 1s denved whrch allows the calculatron of the variation of the chemical potentials of the binary components across the product layer consrdermg the vanatron of the product phase composition A value of A0 = 6 KJ mole-’ 1s estimated for the standard affinity for the formation of storchrometrrc Ag, Hg14 from the binary components AgI and Hg12. Recewed 19 December 1980 Revised 20 March 198 1
12.
THE MAGNETIC BEI-IAVIOUR OF DILUTED CrAl ALLOYS I Pop, D. Dadlrlat, T. Petrrsor and A. Gmrgm, Department of Physrcs, Cluj-Napoca University, 3400 CluJ-Napoca, Romania
Magnetic susceptrbrhty as a function of temperature of binary CrAl alloys contammg 0.7, 1.07, 1 35, 1.59, 1.79, 1.98,2.18, 2.84,3.74 and 4.36 at.% Al 1s mvestigated. Alummmm, by alloymg, acts on the Neel temperature of pure chrommm gwmg rrse to a complicated phase diagram The behavrour of the magnetic susceptrbility as a function of temperature, m the ordered phase, for the samples contammg 1 28,2.18 and 2.84 at.% Al 1s found to be temperature independent. In the paramagnetrc region, for the samples contaimng between 1.07