Berichte der Bunsengesellschaft für physikalische Chemie最新文献_第6页

Electron-Energy-Loss Spectroscopy of Spin-Forbidden Transitions with Vibronic Resolution: The Lowest Triplet State of Fluorobenzenes 具有振动分辨率的自旋禁止跃迁的电子能量损失光谱:氟苯的最低三重态

Berichte der Bunsengesellschaft für physikalische Chemie Pub Date : 2014-03-18 DOI: 10.1002/bbpc.199700015

P. Swiderek, S. Schürfeld, H. Winterling

{"title":"Electron-Energy-Loss Spectroscopy of Spin-Forbidden Transitions with Vibronic Resolution: The Lowest Triplet State of Fluorobenzenes","authors":"P. Swiderek, S. Schürfeld, H. Winterling","doi":"10.1002/bbpc.199700015","DOIUrl":"10.1002/bbpc.199700015","url":null,"abstract":"Low-energy electron-energy-loss spectra in the range of the lowest triplet state are presented for solid benzene, fluorobenzene, and p-difluorobenzene deposited at a temperature of 30 K. Vibronic structure within the triplet bands of fluorobenzene and p-difluorobenzene is observed for the first time. The spectrum of fluorobenzene closely resembles that of benzene, whereas p-difluorobenzene shows characteristic differences. The spectra of all three molecules are dominated by pure progressions of the totally symmetric ring-breathing vibrational mode v1. In addition, less intense transitions to vibronic levels relating to the e2g modes in benzene are observed and their assignment is given. The occurrence of e2g modes in all three spectra underlines that the vibronic coupling pathways between the lowest and the second triplet state are similar in benzene and its derivatives. In p-difluorobenzene a splitting of the extremely low frequency mode that relates to the v8 (e2g) vibration in benzene is observed. This is in agreement with theoretical predictions of an asymmetric shape of the lowest triplet potential energy surface along a symmetry coordinate relating to v8 in substituted benzenes.","PeriodicalId":100156,"journal":{"name":"Berichte der Bunsengesellschaft für physikalische Chemie","volume":"101 10","pages":"1517-1526"},"PeriodicalIF":0.0,"publicationDate":"2014-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/bbpc.199700015","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"105734101","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

Ab Initio Modelling of Defects in Non-Metallic Systems 非金属系统缺陷的从头算建模

Berichte der Bunsengesellschaft für physikalische Chemie Pub Date : 2014-03-18 DOI: 10.1002/bbpc.199700025

R. Jones

引用次数: 1

Viscosity Measurements on Molten Salts with an Oscillating Cup Viscometer: Viscosity of Molten KNO3 and NaCl 用振荡杯粘度计测量熔盐的粘度:熔融KNO3和NaCl的粘度

Berichte der Bunsengesellschaft für physikalische Chemie Pub Date : 2014-03-18 DOI: 10.1002/bbpc.199800007

D. Tolbaru, Rodica Borcan, Stefania Zuca

{"title":"Viscosity Measurements on Molten Salts with an Oscillating Cup Viscometer: Viscosity of Molten KNO3 and NaCl","authors":"D. Tolbaru, Rodica Borcan, Stefania Zuca","doi":"10.1002/bbpc.199800007","DOIUrl":"10.1002/bbpc.199800007","url":null,"abstract":"An oscillating cup viscometer interfaced to an automatic data acquisition and processing system (computer, interface, software) was built for viscosity measurements in molten salts below 1400 K.In order to avoid the “meniscus effect”, the main source of errors of the method, the measurements were carried out in the so-called “full cup” condition, i.e. with the height of the liquid column (h) of 11.2 cm, the overall height of the cup being 11.9 cm. An adequate software supplied η values at each temperature, as function of R, I, δ, h, ρ and T values in air and with liquid containing cup. The viscosity of molten KNO3 and NaCl, both of “standard salt purity”, was reinvestigated over a temperature range of 100 K above their melting points. The standard deviation of the data obtained was ±0.38%. These data were systematically lower (3% for ηNaCl and 2% for η) than those obtained earlier by the same method, but agree within ±0.9% with the recommended Janz's “calibration quality viscosity data”.One can conclude that the method gives accurate results only if operated in “full cup” condition.","PeriodicalId":100156,"journal":{"name":"Berichte der Bunsengesellschaft für physikalische Chemie","volume":"102 10","pages":"1387-1392"},"PeriodicalIF":0.0,"publicationDate":"2014-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/bbpc.199800007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"96818281","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: 8

Simulation of Electrical Properties of Grain Boundaries in Titanate Ceramics 钛酸盐陶瓷晶界电学性能的模拟

Berichte der Bunsengesellschaft für physikalische Chemie Pub Date : 2014-03-18 DOI: 10.1002/bbpc.199700032

R. Hagenbeck, R. Waser

{"title":"Simulation of Electrical Properties of Grain Boundaries in Titanate Ceramics","authors":"R. Hagenbeck, R. Waser","doi":"10.1002/bbpc.199700032","DOIUrl":"10.1002/bbpc.199700032","url":null,"abstract":"Using a numerical simulation method, the electrostatic properties of grain boundaries in titanate ceramics (SrTiO3 and BaTiO3) are calculated by the combination of a defect chemistry model and the general potential equation. Based on these results and a simple three-dimensional “brick-wall-model” of the ceramic microstructure, an equivalent network is developed for the ceramic body which consists of a great number of R C-branches. Using this network it is possible to calculate the frequency dependence of the complex impedance of the ceramic. The results of the impedance simulation can be compared to experimental results. This comparison yields information about the charge transport across and along the grain boundaries and about the influence of the temperature, the bulk dopant concentrations, and the donor- or acceptor-like grain boundary interface states on the electrical properties of the grain boundaries. By using the simulation technique one gets additional information to interpret and understand the experimental results and to model the physical and electrical behaviour of the grain boundaries which mainly determine the electrical characteristics of the ceramic.","PeriodicalId":100156,"journal":{"name":"Berichte der Bunsengesellschaft für physikalische Chemie","volume":"101 9","pages":"1238-1241"},"PeriodicalIF":0.0,"publicationDate":"2014-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/bbpc.199700032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"112372343","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

P. W. Atkins: Memofix Physikalische Chemie kurz und bündig von A–Z, VCH Verlagsgesellschaft, Weinheim, 1996 a z, VCH出版公司，温汉1996年

Berichte der Bunsengesellschaft für physikalische Chemie Pub Date : 2014-03-18 DOI: 10.1002/bbpc.199700022

Hans-Jürgen Bär

引用次数: 0

Vapour Pressures at Eight Temperatures of Mixtures of Di-n-Propylether + Ethanol, or +1-Butanol – Thermodynamic Description of Mixtures of Di-n-Propylether + Alkanol According to the ERAS Model 双正丙醚+乙醇或+1-丁醇混合物在八种温度下的蒸汽压-根据ERAS模型对双正丙醚+醇混合物的热力学描述

Berichte der Bunsengesellschaft für physikalische Chemie Pub Date : 2014-03-18 DOI: 10.1002/bbpc.199700008

R. Garriga, P. Pérez, M. Gracia

引用次数: 17

Einladung zur 97. Hauptversammlung der Deutschen Bunsen-Gesellschaft für Physikalische Chemie e.V. vom 21. bis 23. Mai 1998 in Münster 97号邀请函德国国立物理化学协会至23 .1998年5月在明斯特

Berichte der Bunsengesellschaft für physikalische Chemie Pub Date : 2014-03-18 DOI: 10.1002/bbpc.199700021

引用次数: 0

WERNER KUTZELNIGG 维尔纳-库策尔尼格

Berichte der Bunsengesellschaft für physikalische Chemie Pub Date : 2014-03-18 DOI: 10.1002/bbpc.199800021

Reinhart Ahlrichs

引用次数: 0

Kinetic Studies on Reversible Dimerization of Thianthrene and 2,3,7,8-Tetramethoxythianthrene Radical Cations 噻吩和2,3,7,8-四甲氧基噻吩自由基阳离子可逆二聚化动力学研究

Berichte der Bunsengesellschaft für physikalische Chemie Pub Date : 2014-03-18 DOI: 10.1002/bbpc.199800020

Patrick Hübler, Jürgen Heinze

{"title":"Kinetic Studies on Reversible Dimerization of Thianthrene and 2,3,7,8-Tetramethoxythianthrene Radical Cations","authors":"Patrick Hübler, Jürgen Heinze","doi":"10.1002/bbpc.199800020","DOIUrl":"10.1002/bbpc.199800020","url":null,"abstract":"Fast scan voltammetry gives kinetic evidence for the reversible dimerization of the radical cations of thianthrene (T) and 2,3,7,8-tetra-methoxythianthrene (TMOT) in acetonitrile. At 256 K an equilibrium constant KDim ≈ 900 for TMOT (KDim ≈ 1.1·104 for T) and rate constants kf ≈ 1·107 and kb ≈ 1.2·104 were determined. Using the semi-empirical PM3 method, the formation of σ-bonded dimers is indicated. For the dimerization reaction in acetonitrile, enthalpy values of −79 kJ/mol for T and −56 kJ/mol for TMOT respectively were calculated. Despite the folded structure of the neutral T and TMOT systems and their planarization during the radical cation formation, the heterogeneous electron transfer kinetics was found to be very fast in both cases (1.6 cm/s; 298 K). The activation enthalpy was determined to be 14 kJ/mol in the case of TMOT. Calculations of the inner-sphere reorganization energy using the Marcus theory produced ΔH#(∞) = 4.6 kJ/mol for TMOT and 3.9 kJ/mol for T respectively at infinite temperatures. This explains the fast electron transfer kinetics and their low activation enthalpies.","PeriodicalId":100156,"journal":{"name":"Berichte der Bunsengesellschaft für physikalische Chemie","volume":"102 10","pages":"1506-1509"},"PeriodicalIF":0.0,"publicationDate":"2014-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/bbpc.199800020","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"105391778","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

FTIR Spectroscopy to Monitor OH-Impurity Interactions in Insulating Crystals FTIR光谱法监测绝缘晶体中oh -杂质相互作用

Berichte der Bunsengesellschaft für physikalische Chemie Pub Date : 2014-03-18 DOI: 10.1002/bbpc.199700037

Rosanna Capelletti, Paola Beneventi, Andrea Ruffini

{"title":"FTIR Spectroscopy to Monitor OH-Impurity Interactions in Insulating Crystals","authors":"Rosanna Capelletti, Paola Beneventi, Andrea Ruffini","doi":"10.1002/bbpc.199700037","DOIUrl":"10.1002/bbpc.199700037","url":null,"abstract":"Hydroxyl ion is a common impurity in insulating crystals: by interacting with other impurities, it gives rise to new complexes. The OH-stretching frequency is a very sensitive probe of the hydroxyl environment. High resolution (0.04 cm_1) FTIR spectroscopy in the temperature range 9–300 K was applied to study the OH-cation impurity interaction in alkali halides, fluoroperovskites, and sillenites, suitable for optoelectronic applications. Proper thermal treatments and isotopic substitutions allowed to assign the stretching mode absorption lines to the defects in which OH– is embedded and to supply possible models for them. Anharmonicity effect of the OH– -stretching modes, monitored by weak overtone lines, were well described in the framework of the Morse model. Electric anharmonicity was also detected. The phonon coupling of the OH–-stretching mode in different defects was studied by analysing the temperature dependence of the line-position and -width: in most cases the single-phonon coupling model accounted for the experimental data and supplied the coupled phonon frequencies.","PeriodicalId":100156,"journal":{"name":"Berichte der Bunsengesellschaft für physikalische Chemie","volume":"101 9","pages":"1265-1273"},"PeriodicalIF":0.0,"publicationDate":"2014-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/bbpc.199700037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"100142931","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