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Group-theoretical framework for characterizing the ring flipping of spiro[5.5]undecane derivatives. Pseudo-point groups and subsymmetry-itemized enumeration 表征螺旋[5.5]十一烷衍生物环翻转的群论框架。伪点群与亚对称逐项枚举
Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A804599B
S. Fujita
{"title":"Group-theoretical framework for characterizing the ring flipping of spiro[5.5]undecane derivatives. Pseudo-point groups and subsymmetry-itemized enumeration","authors":"S. Fujita","doi":"10.1039/A804599B","DOIUrl":"https://doi.org/10.1039/A804599B","url":null,"abstract":"The pseudo-point group DD2d for characterizing the flipping of the two cyclohexane rings in spiro[5.5]undecane is defined. Spirane derivatives with a given formula and a given symmetry are enumerated by the unit-subduced-cycle-index (USCI) approach on the basis of the spiro[5.5]undecane skeleton. The symmetry of each derivative corresponds to one of the subgroups of DD2d, which are classified into isoenergetic (isoenergetic-achiral and isoenergetic-chiral) or anisoenergetic (anisoenergetic-achiral and anisoenergetic-chiral) ones. The orbits in the derivative are discussed by the sphericity and chronality.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76852887","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: 3
Progress in electronic spectroscopy of large molecules 大分子电子能谱研究进展
Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A801202D
J. Hollas
{"title":"Progress in electronic spectroscopy of large molecules","authors":"J. Hollas","doi":"10.1039/A801202D","DOIUrl":"https://doi.org/10.1039/A801202D","url":null,"abstract":"The use of lasers and, particularly, the supersonic jet or molecular beam has revolutionised the electronic spectroscopy of molecules of the size of benzene, or larger. With the extreme rotational and vibrational cooling in the jet much of the congestion observed in the spectrum at room temperature is removed. To resolve individual rotational lines it is necessary to remove most of the Doppler broadening. The techniques most often employed are either to use a skimmed supersonic jet, to leave only the core molecular beam, or to arrange to observe only the core. Fluorescence excitation, or resonant multiphoton ionisation, provides vibrational or high-resolution rotational information about the excited electronic state. Single vibronic level (or dispersed) fluorescence is used to obtain vibrational information about the ground state. Structural and conformational information about these molecules, in both their ground and excited states, much of it difficult to obtain in any other way, can be obtained by these techniques.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76875574","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
Polarizability and hyperpolarizability of push–pull quinoid molecules Simulation of donor–acceptor pairs 推拉类醌分子的极化性和超极化性
Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A802313A
Y. Sheng, Yuansheng Jiang
{"title":"Polarizability and hyperpolarizability of push–pull quinoid molecules Simulation of donor–acceptor pairs","authors":"Y. Sheng, Yuansheng Jiang","doi":"10.1039/A802313A","DOIUrl":"https://doi.org/10.1039/A802313A","url":null,"abstract":"AM1 calculations are performed to study the non-linear optical (NLO) properties of push–pull quinones. The variations of molecular structure, linear (α) and NLO polarizabilities (β, γ) for a set of push–pull quinones are discussed in terms of quinoid–benzenoid character (QBC), and the strength of donor–acceptor pairs (δDA). The parameter δDA, already used for the polyenebridge, is still valid in rationalizing the donor–acceptor strength for quinoid derivatives. In addition, we examined how an external electric field created by ‘Sparkles’ in the MOPAC package drives a quinoid molecule from the quinoid limit to the benzenoid limit, and how it affects the NLO properties. The results show that the effect produced by Sparkles is qualitatively similar to that of donor–acceptor pairs.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78197105","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: 9
NO adsorption on a single crystal and a polycrystalline powder of LiNbO3 LiNbO3单晶和多晶粉末对NO的吸附
Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A801308J
K. Tabata, M. Kamada, T. Choso, Y. Nagasawa
{"title":"NO adsorption on a single crystal and a polycrystalline powder of LiNbO3","authors":"K. Tabata, M. Kamada, T. Choso, Y. Nagasawa","doi":"10.1039/A801308J","DOIUrl":"https://doi.org/10.1039/A801308J","url":null,"abstract":"NO has been adsorbed as NO2− and NO3− on an LiNbO3 single crystal at room temperature. NO− was observed in the XPS spectrum for the N 1s level of the LiNbO3 single crystal after exposure at 200 and 400 °C, respectively. An LiNbO3 polycrystalline powder had only a peak from NO3− after exposure between room temperature and 400 °C. The oxygen vacancies of lattice oxygen were produced with both LiNbO3 samples after exposure at room temperature. These oxygen vacancies in the LiNbO3 single crystal were partially refilled with NO− after exposure at 200 and 400 °C. On the other hand, the vacancies associated with the polycrystalline powder were partially refilled by the out-diffusion of oxygen ions from the bulk to the surface after exposure at 200 and 400 °C. The ions of lithium and oxygen in the bulk LiNbO3 polycrystalline powder diffuse more easily to its surface than those present in the LiNbO3 single crystal.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78202020","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: 7
Critical initial conditions for spontaneous thermal ignition 热自燃的临界初始条件
Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A806516K
R. Weber, E. Balakrishnan, G. Wake
{"title":"Critical initial conditions for spontaneous thermal ignition","authors":"R. Weber, E. Balakrishnan, G. Wake","doi":"10.1039/A806516K","DOIUrl":"https://doi.org/10.1039/A806516K","url":null,"abstract":"Critical initial conditions for thermal ignition are calculated numerically for planar, cylindrical and spherical geometries. In each case a comparison is made on the bifurcation diagram with the intermediate steady state(s). It is clearly seen that the actual critical initial condition which depends upon the initial temperature profile, is partly below the intermediate steady state(s). The variation with ambient temperature, exothermicity and Biot number are all explicitly shown. The results are important for calculations relevant to the critical hot product assembly problem where a hot manufactured organic product is packed into containers or stockpiled at a subcritical ambient storage temperature. An example calculation for an interesting case study (milk powder) is given to illustrate the utility of our results.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75131447","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
Photocatalytic activities and photophysical properties of Ga2−xInxO3 solid solution Ga2−xInxO3固溶体的光催化活性和光物理性质
Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A805563G
A. Kudo, I. Mikami
{"title":"Photocatalytic activities and photophysical properties of Ga2−xInxO3 solid solution","authors":"A. Kudo, I. Mikami","doi":"10.1039/A805563G","DOIUrl":"https://doi.org/10.1039/A805563G","url":null,"abstract":"Photocatalytic activities of Ga2−xInxO3 solid solutions consisting of β-Ga2O3 with a wide band gap and In2O3 with a medium band gap were studied in order to develop new photocatalysts based on oxide solid solutions. The Ga2−xInxO3 solid solutions were characterized by X-ray diffraction, surface area, diffuse reflection spectra, photoluminescent and photoelectrochemical measurements. As the ratio of In was increased from x = 0 to 1 in Ga2−xInxO3, the lattice parameters were increased, indicating the formation of solid solutions as has previously been reported. Corresponding to this, the absorption, excitation and emission spectra were red-shifted, showing a decrease in the band gaps, and the flat band potentials were shifted positively. Among the solid solutions, GaInO3 (or Ga1.14In0.86O3) showed the highest photocatalytic activity for H2 evolution from aqueous methanol solutions and for O2 evolution from aqueous silver nitrate solutions. The dependency of the photocatalytic activities on the composition of the solid solutions was explained by taking the number of available photons and the flat band potentials into consideration.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75224577","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: 71
Influence of ion exchange and calcination on pore size and thermal stability of MCM-41 with different Si/Al ratios 离子交换和煅烧对不同Si/Al比MCM-41孔径和热稳定性的影响
Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A707287B
H. Koch, U. Böhmer, A. Klemt, W. Reschetilowski, M. Stöcker
{"title":"Influence of ion exchange and calcination on pore size and thermal stability of MCM-41 with different Si/Al ratios","authors":"H. Koch, U. Böhmer, A. Klemt, W. Reschetilowski, M. Stöcker","doi":"10.1039/A707287B","DOIUrl":"https://doi.org/10.1039/A707287B","url":null,"abstract":"A decrease in pore size and increase in thermal stability of three different MCM-41 materials with Si/Al ratios of 18.6, 17.3 and 3.1, due to ammonia ion exchange and following calcination at 540°C, has been observed by N2 sorption measurements, differential thermal analysis (DTA) and X-ray diffraction (XRD). An explanation based on recrystallization at the pore mouth is proposed and the influence of the alumina content of the materials is discussed.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75243318","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: 11
Excited state interactions of thiopyrylium salts 硫代镱盐的激发态相互作用
Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A707307K
F. Morlet‐Savary, S. Parret, J. Fouassier, K. Inomata, Takeo Matsumoto
{"title":"Excited state interactions of thiopyrylium salts","authors":"F. Morlet‐Savary, S. Parret, J. Fouassier, K. Inomata, Takeo Matsumoto","doi":"10.1039/A707307K","DOIUrl":"https://doi.org/10.1039/A707307K","url":null,"abstract":"The photophysics and photochemistry of thiopyrylium salts have been investigated by UV–VIS absorption spectroscopy and nanosecond laser absorption spectroscopy. The effect of substituents of the heterocycle on the photophysical properties was analysed. Dissociation of peroxidic compounds photosensitized by these salts was studied. The interaction with monomers and many other additives has also been investigated. A mechanism is proposed for the initiation of acrylic photopolymerization reactions.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76087960","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: 15
Single-crystal and multi-frequency EPR studies on chemical analogues of Amavadin: V(IV)-doped Ca[Ti(hida)2]·6H2O, and Mo(V)-doped [PPh4][Nb(hida)2] and [NEt4][Ta(R,R-hidpa)2] [H3hida=2,2′-(hydroxyimino)diacetic acid, H3hidpa=2,2′-(hydroxyimino)dipropionic acid] Amavadin化学类似物的单晶和多频EPR研究:V(IV)掺杂Ca[Ti(hida)2]·6H2O和Mo(V)掺杂[PPh4][Nb(hida)2]和[NEt4][Ta(R,R-hidpa)2] [H3hida=2,2 ' -(羟亚胺)二乙酸，H3hidpa=2,2 ' -(羟亚胺)二丙酸]
Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A804499F
E. McInnes, F. Mabbs, Spencer M. Harben, P. D. Smith, D. Collison, C. Garner, Graham M. Smith, P. Riedi
{"title":"Single-crystal and multi-frequency EPR studies on chemical analogues of Amavadin: V(IV)-doped Ca[Ti(hida)2]·6H2O, and Mo(V)-doped [PPh4][Nb(hida)2] and [NEt4][Ta(R,R-hidpa)2] [H3hida=2,2′-(hydroxyimino)diacetic acid, H3hidpa=2,2′-(hydroxyimino)dipropionic acid]","authors":"E. McInnes, F. Mabbs, Spencer M. Harben, P. D. Smith, D. Collison, C. Garner, Graham M. Smith, P. Riedi","doi":"10.1039/A804499F","DOIUrl":"https://doi.org/10.1039/A804499F","url":null,"abstract":"Q-band single-crystal and powder EPR spectra at multiple frequencies (X, Q and 180 GHz) of V(IV)-doped Ca[Ti(hida)2]·6H2O and Mo(V)-doped [PPh4][Nb(hida)2] and [NEt4][Ta(R,R-hidpa)2] (H3hida=2,2′-(hydroxyimino)diacetic acid; H3hidpa 2,2′-(hydroxyimino)dipropionic acid) are reported. The Ti{V} system has the spin-Hamiltonian parameters g11=1.910, g22=1.987, g33=1.990, A11=176.4 G, A22=53.5 G and A33=46.3 G with non-coincidence between the principal axes of the g- and A-matrices. The Euler angles for the non-concidence are α=11.5°, χ=4.63° and γ=346.0°. The triclinic EPR symmetry is consistent with the low (C1) point symmetry of the [Ti{V}(hida)2]2- anion in the solid state. The small angles of non-coincidence between the principal axes of the g and A matrices are also evident from the Q-band powder spectrum, but not the X-band spectrum. High-frequency (34–180 GHz) EPR measurements on powders of both the Nb{Mo} and Ta{Mo} systems reveal the presence of two magnetically distinct Mo centers in each case. The Nb{Mo} system has g-values of g11(a)=1.9765, g11(b)=1.9755, g22(a)=1.9675, g22(b)=1.9665, g33(a)=1.8870 and g33(b)=1.8840, while the Ta{Mo} system has g11(a)=1.976, g11(b)=1.974, g22(a)=1.970, g22(b)=1.967, g33(a)=1.894 and g33(b)=1.892.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75649901","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: 2
Deposition mechanism of BC2.5N heterodiamond under shock compression BC2.5N异质金刚石在冲击压缩下的沉积机理
Journal of the Chemical Society, Faraday Transactions Pub Date : 1998-01-01 DOI: 10.1039/A800461G
T. Komatsu, M. Nomura, Y. Kakudate, S. Fujiwara
{"title":"Deposition mechanism of BC2.5N heterodiamond under shock compression","authors":"T. Komatsu, M. Nomura, Y. Kakudate, S. Fujiwara","doi":"10.1039/A800461G","DOIUrl":"https://doi.org/10.1039/A800461G","url":null,"abstract":"Transmission electron microscopy of shock compacted hexagonal BC2.5N indicated the coexistence of morphologically and compositionally complex materials, a large proportion of cubic BC2.5N (heterodiamond), trace amounts of amorphous heterodiamond, atomic-rearranged cubic BC2.5N, an amorphous diamond-like material and onion-like heterofullerene. Such diversities of the products suggested liquid phase-to-solid phase deposition that is affected by the local heterogeneity in the cooling medium surrounding the liquid phase. The possibility of this mechanism was also suggested by kinetic estimations of the shock-compression process.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74611761","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: 5
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