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Quantum dynamical characterization of unimolecular resonances 单分子共振的量子动力学表征
PhysChemComm Pub Date : 2003-03-03 DOI: 10.1039/B300284P
Hong Zhang, Sean C. Smith
{"title":"Quantum dynamical characterization of unimolecular resonances","authors":"Hong Zhang, Sean C. Smith","doi":"10.1039/B300284P","DOIUrl":"https://doi.org/10.1039/B300284P","url":null,"abstract":"We give a selective review of quantum mechanical methods for calculating and characterizing resonances in small molecular systems, with an emphasis on recent progress in Chebyshev and Lanczos iterative methods. Two archetypal molecular systems are discussed: isolated resonances in HCO, which exhibit regular mode and state specificity, and overlapping resonances in strongly bound HO2, which exhibit irregular and chaotic behavior. Future directions in this field are also discussed.","PeriodicalId":20106,"journal":{"name":"PhysChemComm","volume":"40 1","pages":"12-20"},"PeriodicalIF":0.0,"publicationDate":"2003-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72813702","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: 1
Non-photochemical spectral hole-burning mediated by water molecules in interligand pockets of [Cr(terpy)2]3+ [Cr(terpy)2]3+配体间隙中水分子介导的非光化学光谱烧孔
PhysChemComm Pub Date : 2003-02-06 DOI: 10.1039/B209460F
H. Riesen, L. Wallace
{"title":"Non-photochemical spectral hole-burning mediated by water molecules in interligand pockets of [Cr(terpy)2]3+","authors":"H. Riesen, L. Wallace","doi":"10.1039/B209460F","DOIUrl":"https://doi.org/10.1039/B209460F","url":null,"abstract":"Low temperature fluorescence line-narrowing (FLN) and spectral hole-burning experiments (SHB) were performed in the 2E←4A2 spin–flip transition of [Cr(2,2′:6′,2″-terpyridine)2]3+ in frozen ethylene glycol/water (2 ∶ 1) and DMSO/water (2 ∶ 1) glasses. In the FLN experiments an average 2E splitting of 23 cm−1 is observed. It is concluded that the interaction with water molecules in pockets provided by the ligands is most likely to be responsible for the relatively efficient non-photochemical hole-burning. Fast spectral diffusion and spontaneous hole-filling prevent the observation of holes above 20 K. The FLN and SHB experiments were performed by using a diode laser.","PeriodicalId":20106,"journal":{"name":"PhysChemComm","volume":"82 1","pages":"9-11"},"PeriodicalIF":0.0,"publicationDate":"2003-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79328590","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: 4
Solvent caging of internal motions in myoglobin at low temperaturesThis paper was originally presented as a poster at the Faraday Discussion 122 meeting. 低温下肌红蛋白内部运动的溶剂笼化这篇论文最初是作为Faraday Discussion 122会议的海报发表的。
PhysChemComm Pub Date : 2003-02-05 DOI: 10.1039/b209839c
A. Tournier, Jiancong Xu, Jeremy C. Smith
{"title":"Solvent caging of internal motions in myoglobin at low temperaturesThis paper was originally presented as a poster at the Faraday Discussion 122 meeting.","authors":"A. Tournier, Jiancong Xu, Jeremy C. Smith","doi":"10.1039/b209839c","DOIUrl":"https://doi.org/10.1039/b209839c","url":null,"abstract":"Experimental and simulation studies have reported the presence of a transition in the internal dynamics of proteins at 220 K. This transition has been correlated with the onset of activity in several proteins. The role of the solvent in the dynamical transition has been the subject of increased attention. Here simulation techniques are used to distinguish dynamical features inherent to the protein energy landscape from those induced by the surrounding solvent. The present results indicate that the protein dynamical transition primarily affects the side-chains on the outer layers of the protein. Moreover, the results indicate that the solvent restrains protein motions at low temperatures.","PeriodicalId":20106,"journal":{"name":"PhysChemComm","volume":"549 1","pages":"6-8"},"PeriodicalIF":0.0,"publicationDate":"2003-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77946767","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: 4
Origin of the sub-diffusive behavior and crossover from sub-diffusive to super-diffusive dynamics near a biological surface 生物表面附近亚扩散行为的起源和从亚扩散到超扩散动力学的交叉
PhysChemComm Pub Date : 2002-12-24 DOI: 10.1039/B212786E
A. Mukherjee, B. Bagchi
{"title":"Origin of the sub-diffusive behavior and crossover from sub-diffusive to super-diffusive dynamics near a biological surface","authors":"A. Mukherjee, B. Bagchi","doi":"10.1039/B212786E","DOIUrl":"https://doi.org/10.1039/B212786E","url":null,"abstract":"Diffusion of a tagged particle near a constraining biological surface is examined numerically by modeling the surface-water interaction by an effective potential. The effective potential is assumed to be given by an asymmetric double well constrained by a repulsive surface towards r \u0000→ 0 and unbound at large distances. The time and space dependent probability distribution P(r,t) of the underlying Smoluchowski equation is solved by using the Crank–Nicholson method. The mean square displacement shows a transition from sub-diffusive (exponent α \u0000≈ 0.46) to a super-diffusive (exponent α \u0000≈ 1.75) behavior with time and ultimately to diffusive dynamics. The decay of self intermediate scattering function (Fs(k,t)) is non-exponential in general and shows a power law behavior at the intermediate time. Such features have been observed in several recent computer simulation studies on the dynamics of water in proteins and micellar hydration shells. The present analysis provides a simple microscopic explanation for the transition from the sub-diffusivity and super-diffusivity. The super-diffusive behavior is due to escape from the well near the surface and the sub-diffusive behavior is due to the return of quasi-free molecules to form the bound state again, after the initial escape.","PeriodicalId":20106,"journal":{"name":"PhysChemComm","volume":"71 1","pages":"28-31"},"PeriodicalIF":0.0,"publicationDate":"2002-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80007387","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: 4
Applicability of thermoacoustical parameters for the computation of available volume in liquid systems 热声参数在液体系统可用体积计算中的适用性
PhysChemComm Pub Date : 2002-01-01 DOI: 10.1039/B109599D
J. D. Pandey, R. Dey, Bishan Datt Bhatt
{"title":"Applicability of thermoacoustical parameters for the computation of available volume in liquid systems","authors":"J. D. Pandey, R. Dey, Bishan Datt Bhatt","doi":"10.1039/B109599D","DOIUrl":"https://doi.org/10.1039/B109599D","url":null,"abstract":"Available volumes in pure liquids and binary liquid mixture at varying temperature have been computed using thermoacoustical parameters and the values thus obtained are compared with the values obtained from a thermodynamic relation of the available volume. Fairly good agreement between the values from the two methods proves the applicability of thermoacoustical parameters for the computation of the available volume in pure liquids and liquid mixtures.","PeriodicalId":20106,"journal":{"name":"PhysChemComm","volume":"45 1","pages":"37-39"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74946677","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: 6
The effect of lithium triflate and lithium bromide on the vibrational frequencies of DMEDA 三酸锂和溴化锂对DMEDA振动频率的影响
PhysChemComm Pub Date : 2002-01-01 DOI: 10.1039/B204103K
Shawna S. York, Scott E. Boesch, R. Wheeler, R. Frech
{"title":"The effect of lithium triflate and lithium bromide on the vibrational frequencies of DMEDA","authors":"Shawna S. York, Scott E. Boesch, R. Wheeler, R. Frech","doi":"10.1039/B204103K","DOIUrl":"https://doi.org/10.1039/B204103K","url":null,"abstract":"An experimental and computational investigation of the structures and vibrational frequencies of N,N′-dimethylethylenediamine–lithium triflate (DMEDA–LiTf; Tf – = CF 3 SO 3 – ) has been done using a combination of hybrid Hartree–Fock/density functional calculations and Raman and IR spectroscopy. Band assignments for DMEDA–LiBr were made by comparing the experimental Raman and IR spectra of a 5 ∶ 1 DMEDA–LiBr sample with the calculated vibrational frequencies of the DMEDA–Li + and DMEDA–LiBr complexes. Band assignments for DMEDA–LiTf were made by comparing the experimental spectra of samples over a composition range of 20 ∶ 1 to 1.5 ∶ 1 with calculations done on the DMEDA–LiTf complexes. The effect of the lithium cation and lithium triflate on the geometries and vibrational frequencies of the DMEDA will be examined. The combined experimental data and computational results clearly show that the intramolecular hydrogen bonding in pure DMEDA is broken upon addition of lithium bromide or lithium triflate.","PeriodicalId":20106,"journal":{"name":"PhysChemComm","volume":"124 5 1","pages":"99-99"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80480966","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: 4
Self-organization of triple-stranded carbon nanoropes 三链碳纳米粒子的自组织
PhysChemComm Pub Date : 2002-01-01 DOI: 10.1039/B110151J
C. Su, D. W. Hwang, S. Lin, Bih-Yaw Jin, L. Hwang
{"title":"Self-organization of triple-stranded carbon nanoropes","authors":"C. Su, D. W. Hwang, S. Lin, Bih-Yaw Jin, L. Hwang","doi":"10.1039/B110151J","DOIUrl":"https://doi.org/10.1039/B110151J","url":null,"abstract":"Novel self-organized carbon nanoropes consisting of three helically coiled multi-wall nanotubes with a remarkable constant pitch over several microns were grown by the lanthanide oxide-catalyzed decomposition of gaseous acetylene on aluminophosphate (AlPO 4 -5) support. Direct characterization by the stereo transmission electron microscope and scanning electron microscope has convincingly shown that these three strands entwine with each other helically, which are presumably kept together by both the spontaneous curvature and van der Waals (vdW) attraction.","PeriodicalId":20106,"journal":{"name":"PhysChemComm","volume":"5 1","pages":"34-36"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73613620","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
Adsorption behaviour of DNA bases at the Au(111) electrode DNA碱基在Au(111)电极上的吸附行为
PhysChemComm Pub Date : 2002-01-01 DOI: 10.1039/B208139C
A. P. M. Camargo, H. Baumgärtel, C. Donner
{"title":"Adsorption behaviour of DNA bases at the Au(111) electrode","authors":"A. P. M. Camargo, H. Baumgärtel, C. Donner","doi":"10.1039/B208139C","DOIUrl":"https://doi.org/10.1039/B208139C","url":null,"abstract":"We report on the adsorption of adenine as well as on the coadsorption of adenine/thymine and uracil/thymine on Au(111). Adenine is chemisorbed in two different states. Mutual interaction between adenine and thymine could be detected only at negative potentials where both molecules are oriented with their plane parallel to the surface. This interaction depends on the concentration of thymine, the pH value, the temperature and the roughness of the surface. At positive potentials where thymine/adenine are oriented perpendicular to the electrode surface, from our experiments no hints to their interaction could be found. Thymine prevents the uracil adsorption and no cocondensation signal between the noncomplementary bases thymine/uracil was found.","PeriodicalId":20106,"journal":{"name":"PhysChemComm","volume":"50 1","pages":"151-157"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82925648","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
Ultrafast vibrational spectroscopy in condensed phases 凝聚相中的超快振动光谱
PhysChemComm Pub Date : 2002-01-01 DOI: 10.1039/B110898K
M. Cho
{"title":"Ultrafast vibrational spectroscopy in condensed phases","authors":"M. Cho","doi":"10.1039/B110898K","DOIUrl":"https://doi.org/10.1039/B110898K","url":null,"abstract":"A variety of ultrafast vibrational excitation and probing methods are first discussed and it is shown that various vibrational spectroscopies can be devised by combining multiple excitation and probing methods. A few ultrafast vibrational spectroscopic methods in condensed phases, which have already been demonstrated and used to study vibrational relaxation phenomena and structural analysis of small polypeptides, are briefly summarized. Then, a number of novel ultrafast vibrational spectroscopies that have been theoretically investigated are discussed by emphasizing their differences from other existing methods. Perspectives on how these ultrafast vibrational spectroscopies in centrosymmetric and non-centrosymmetric condensed phases can be applied to the investigations of chemical reaction dynamics, solvation dynamics, time-dependent structural evolutions of polyatomic molecules such as proteins will be mentioned.","PeriodicalId":20106,"journal":{"name":"PhysChemComm","volume":"40 1","pages":"40-58"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81407617","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
Mesoporous silicates as nanoreactors for synthesis of carbon nanotubes 介孔硅酸盐作为碳纳米管合成的纳米反应器
PhysChemComm Pub Date : 2002-01-01 DOI: 10.1039/B203767J
M. Urbán, Z. Kónya, D. Mehn, Ji Zhu, I. Kiricsi
{"title":"Mesoporous silicates as nanoreactors for synthesis of carbon nanotubes","authors":"M. Urbán, Z. Kónya, D. Mehn, Ji Zhu, I. Kiricsi","doi":"10.1039/B203767J","DOIUrl":"https://doi.org/10.1039/B203767J","url":null,"abstract":"Multi-wall carbon nanotubes (MWNT) were synthesized by a novel method using mesoporous MCM-41 and MCM-48 silicates as nanoreactors in the absence of any metal traces. Transmission electron microscopy (TEM) studies revealed that the quality of carbon nanotubes obtained was very promising, the diameter distribution is very narrow.","PeriodicalId":20106,"journal":{"name":"PhysChemComm","volume":"73 1","pages":"138-141"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76490276","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: 4
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