Discussions of The Faraday Society最新文献_第5页

Exciton-induced photocurrents in molecular crystals 分子晶体中激子诱导的光电流

Discussions of The Faraday Society Pub Date : 1971-01-01 DOI: 10.1039/DF9715100048

H. Baessler, H. Killesreiter, G. Vaubel

引用次数: 18

Infra-red spectroscopic study of the adsorption of amines on the A-type and B-type hydroxyls of an aerosil silica gel 气相硅凝胶a型和b型羟基对胺吸附的红外光谱研究

Discussions of The Faraday Society Pub Date : 1971-01-01 DOI: 10.1039/DF9715200066

F. V. Cauwelaert, F. Vermoortele, J. Uytterhoeven

{"title":"Infra-red spectroscopic study of the adsorption of amines on the A-type and B-type hydroxyls of an aerosil silica gel","authors":"F. V. Cauwelaert, F. Vermoortele, J. Uytterhoeven","doi":"10.1039/DF9715200066","DOIUrl":"https://doi.org/10.1039/DF9715200066","url":null,"abstract":"The interaction of the homogeneous series of primary, secondary and tertiary amines with the free hydroxyls (A-type) and hydrogen-bonded hydroxyls (B-type) of an Aerosil silica is investigated by i.-r.-spectroscopy. The shift Δν of the 3750 cm–1 band (A-type OH) toward lower frequency on adsorption of amines is correlated with the ionization potential I(eV), indicating that charge-transfer contributes strongly to the hydrogen bonding interaction. To investigate the possibility that steric effects of substituent groups in the adsorbate molecule influence the hydrogen-bonding interaction, Δν was also related to the Taft factors σ* and Es, which reflect the polar and steric effects of the substituent groups. A linear (Δν, σ*) relation is found with strong deviation for the tertiary amines. This deviation can be explained either by a steric effect between adsorbate molecule and surface groups, or by the different molecular symmetry of tertiary amines which gives this series a separate but parallel behaviour to the two other series. The extent of interaction of the amines with the B-type hydroxyls is greater for ammonia and the primary amines, than for the secondary and tertiary. This different behaviour is explained by the different packing of the adsorbing molecule. The higher the packing, the lower the proportion of species reacting.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"1 1","pages":"66-76"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88700667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 27

Fluorescence depolarization in sheared solutions of dye-tagged polymers 染料标记聚合物剪切溶液中的荧光去极化

Discussions of The Faraday Society Pub Date : 1970-01-01 DOI: 10.1039/DF9704900268

S. Claesson, H. Odani

引用次数: 8

Vibrational spectra of simple silicate glasses 简单硅酸盐玻璃的振动光谱

Discussions of The Faraday Society Pub Date : 1970-01-01 DOI: 10.1039/DF9705000082

P. Gaskell

引用次数: 37

Atomic vibrations in vitreous silica 玻璃状二氧化硅中的原子振动

Discussions of The Faraday Society Pub Date : 1970-01-01 DOI: 10.1039/DF9705000055

R. J. Bell, P. Dean

引用次数: 399

Nucleation efficiency in lithia-alumina-silica glasses 锂-铝-硅玻璃的成核效率

Discussions of The Faraday Society Pub Date : 1970-01-01 DOI: 10.1039/DF9705000214

T. I. Barry, L. Lay, R. Miller

引用次数: 23

Role of short-range order in producing an energy gap in amorphous covalent semiconductors 非晶共价半导体中短距离有序在产生能隙中的作用

Discussions of The Faraday Society Pub Date : 1970-01-01 DOI: 10.1039/DF9705000020

J. Klima, T. C. Mcgill, J. Ziman

引用次数: 11

Glassy phase separation in sodium borosilicate glasses 硼硅酸钠玻璃的玻璃相分离

Discussions of The Faraday Society Pub Date : 1970-01-01 DOI: 10.1039/DF9705000175

S. Scholes, F. Wilkinson

引用次数: 23

Electrical conductivity of melts and their ability to form glasses in the system Ge + As + Te 熔体的电导率及其在Ge + As + Te体系中形成玻璃的能力

Discussions of The Faraday Society Pub Date : 1970-01-01 DOI: 10.1039/DF9705000035

H. Krebs, P. Fischer

{"title":"Electrical conductivity of melts and their ability to form glasses in the system Ge + As + Te","authors":"H. Krebs, P. Fischer","doi":"10.1039/DF9705000035","DOIUrl":"https://doi.org/10.1039/DF9705000035","url":null,"abstract":"In the system Ge + As + Te, the heavy Te atom facilitates the formation of mesomeric pσ-bonding systems. The glass forming regions are thus small and depend strongly on the quenching conditions. As in the systems Ge + Sb + Se and Ge + As + Se all metallically conducting melts in the system Ge + As + Te solidify to a crystallline structure even when quenched in water. However, not all semiconducting melts belonging to this system become glassy under these conditions. As expected, the transition from melts solidifying to a glass structure to those solidifying to a crystalline structure is more gradual, as is also the transition from metallic to semiconducting melts. All the semiconducting melts become more or less metallically conducting at temperatures between 900 and 1000 °C. The transition can be described by a parabolical or a log log dependence on temperature.In the chalcogenide systems the melting process often enforces the same bonding mechanism with similar atomic short range order as does the application of high pressures or of strong electric fields. This is especially the case at high temperatures. The enforced mobility of the atoms, their tighter packing and the effect of electrical conductivity often act in the same direction, enhancing structural changes in the same direction.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"73 1","pages":"35-44"},"PeriodicalIF":0.0,"publicationDate":"1970-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88522715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 26

Conduction in glassy and liquid semiconductors 玻璃和液体半导体的传导

Discussions of The Faraday Society Pub Date : 1970-01-01 DOI: 10.1039/DF9705000007

N. Mott

{"title":"Conduction in glassy and liquid semiconductors","authors":"N. Mott","doi":"10.1039/DF9705000007","DOIUrl":"https://doi.org/10.1039/DF9705000007","url":null,"abstract":"It is frequently stated that amorphous semiconductors have, in contrast to crystals, a value of the conductivity which is relatively insensitive to composition. This is explained by assuming that each atom in a glass has as many nearest neighbours as the number of bonds it can from (Ge, 4; As, 3; Te, 2), so that there are no free electrons available to carry a current. The validity of this concept will be examined; it is not true for some amorphous films (Mg-Bi) which are not strongly bonded. Also some glasses, when heated above the softening point, seem to change their coordination numbers and become metallic.The theoretical models necessary to describe these results are outlined. In liquid metals and most amorphous metal films, the Ziman theory should be applicable, giving a conductivity equal to Se2L/12π3ħ, where S is the Fermi surface area and L the mean free path. When this is about 3000 Ω–1 cm–1, L is comparable with the distance between atoms and it cannot be smaller. For materials such as liquid Te for which the conductivity is lower, a “pseudogap” affects the conductivity. The lowest possible metallic conductivity is about 200 Ω–1 cm–1. For materials (liquids or non-crystalline solids) with lower conductivity, the current is due either to electrons excited to the “mobility shoulder” or to hopping conduction of the kind familiar in impurity conduction. A real gap (as contrasted with a pseudogap) must exist in transparent materials, and can be understood in terms of the tight-binding approximation.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"42 1","pages":"7-12"},"PeriodicalIF":0.0,"publicationDate":"1970-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87099963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10