Excitation and fluorescence spectra of benzonitrile-benzene and toluene complexes seeded in helium and expanded in a supersonic free jet reveals two types of transition attributed to the coexistence of two isomeric forms. One consists of narrow bands in both excitation and emission and is characteristic of wealdy perturbed van tier Waals complexes. The other involves broadened absorption and gives rise to an exciplex type emission.
{"title":"Spectroscopy and Dynamics of Benzonitrile-Enzene Complexes in A Supersonic Free-Jet","authors":"F. Lahmani, C. Lardeux‐Dedonder, A. Zehnacker","doi":"10.1155/1989/65147","DOIUrl":"https://doi.org/10.1155/1989/65147","url":null,"abstract":"Excitation and fluorescence spectra of benzonitrile-benzene and toluene complexes seeded in helium and \u0000expanded in a supersonic free jet reveals two types of transition attributed to the coexistence of two \u0000isomeric forms. One consists of narrow bands in both excitation and emission and is characteristic of \u0000wealdy perturbed van tier Waals complexes. The other involves broadened absorption and gives rise to an \u0000exciplex type emission.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123432042","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}
D. Baunsgaard, M. E. Balsami, J. Frederiksen, N. Harrit, F. Negri, G. Orlandi, R. Wilbrandt
The phosphorescence spectra of triphenylene and truxene, recorded in glassy solvents at 77 K, are presented. Their vibronic structure is interpreted on the basis of intensities computed with the help of quantum-chemical calculations. The agreement between observed and simulated intensities is very satisfactory and contributes to improve and complete the assignment of ground state frequencies of the two disk-like molecules.
{"title":"THE PHOSPHORESCENCE SPECTRA OF TRIPHENYLENE AND TRUXENE: A COMBINED EXPERIMENTAL AND THEORETICAL INVESTIGATION OF THE VIBRONIC STRUCTURE","authors":"D. Baunsgaard, M. E. Balsami, J. Frederiksen, N. Harrit, F. Negri, G. Orlandi, R. Wilbrandt","doi":"10.1155/1999/25873","DOIUrl":"https://doi.org/10.1155/1999/25873","url":null,"abstract":"The phosphorescence spectra of triphenylene and truxene, recorded in glassy solvents at 77 K, are presented. Their vibronic structure is interpreted on the basis of intensities computed with the help of quantum-chemical calculations. The agreement between observed and simulated intensities is very satisfactory and contributes to improve and complete the assignment of ground state frequencies of the two disk-like molecules.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121885777","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}
Chemiluminescence cross sections for reaction of the individual spin–orbit states of metastable Ca(PJ03) with CH3I, CH2I2, and SF6 have been determined by the use of optical pumping state selection. This technique was also used to separate the chemiluminescence arising from the two excited metastable Ca 3P0 and 1D states. The spin–orbit dependence of the chemiluminescence pathway was found to be substantial for the CH3I and CH2I2 reactions and similar to that previously observed for halogen diatom and alkyl bromide reagents. By contrast, no spin–orbit effect was observed for Ca(3P0)
{"title":"The Reaction of Spin–Orbit State-Selected Ca(PJ03) With CH3I, CH2I2, and SF6","authors":"M. L. Campbell, N. Furio, P. Dagdigian","doi":"10.1155/LC.6.391","DOIUrl":"https://doi.org/10.1155/LC.6.391","url":null,"abstract":"Chemiluminescence cross sections for reaction of the individual spin–orbit states of metastable Ca(PJ03) with CH3I, CH2I2, and SF6 have been determined by the use of optical pumping state selection. This technique was also used to separate the chemiluminescence arising from the two excited metastable Ca 3P0 and 1D states. The spin–orbit dependence of the chemiluminescence pathway was found to be substantial for the CH3I and CH2I2 reactions and similar to that previously observed for halogen diatom and alkyl bromide reagents. By contrast, no spin–orbit effect was observed for Ca(3P0)","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122064373","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}
Colin G. Coates, J. McGarvey, S. Bell, L. Jacquet, J. Kelly, T. Keyes, J. Vos
Transient resonance Raman (TR2) spectroscopy has been used to investigate the metalligand charge-transfer (MLCT) excited states of Ru(II) polypyridyl complexes inDNAand in homogeneous solution. In DNA, complexes of the type [Ru(L)2(L′)]2
{"title":"Transient Resonance RamanStudies of Ru(II) Complexes in DNAand in Homogeneous Media","authors":"Colin G. Coates, J. McGarvey, S. Bell, L. Jacquet, J. Kelly, T. Keyes, J. Vos","doi":"10.1155/1999/74587","DOIUrl":"https://doi.org/10.1155/1999/74587","url":null,"abstract":"Transient resonance Raman (TR2) spectroscopy has been used to investigate the metalligand charge-transfer (MLCT) excited states of Ru(II) polypyridyl complexes inDNAand in homogeneous solution. In DNA, complexes of the type [Ru(L)2(L′)]2","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122177329","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}
In this review we describe the development and the applications of the picosecond-jet technique, which utilizes a picosecond laser and a supersonically-cold jet beam of large molecules. The applications include studies of coherence (quantum beats), photodissociation, isomerization, and partial solvation. The results emphasize the role of intramolecular energy redistribution, and provide evidence for intramolecular threshold effect for rates vs. excess molecular energy. Simple theory for this redistribution of energy among certain modes in molecules is given, and comparison with RRKM calculation is also made to assess the nature of the statistical behavior for the redistribution.
{"title":"Picosecond Laser Chemistry in Supersonic Jet Beams","authors":"A. Zewail","doi":"10.1155/LC.2.55","DOIUrl":"https://doi.org/10.1155/LC.2.55","url":null,"abstract":"In this review we describe the development and the applications of the picosecond-jet technique, which utilizes a picosecond laser and a supersonically-cold jet beam of large molecules. The applications include studies of coherence (quantum beats), photodissociation, isomerization, and partial solvation. The results emphasize the role of intramolecular energy redistribution, and provide evidence for intramolecular threshold effect for rates vs. excess molecular energy. Simple theory for this redistribution of energy among certain modes in molecules is given, and comparison with RRKM calculation is also made to assess the nature of the statistical behavior for the redistribution.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123920097","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}
During the past decade, extensive research has been carried out to utilize the unique characteristics of laser light. Mainly the high intensity, short pulse and small divergence of the laser beam have been made use of, and some of the results are briefly summarized here. The effect of the coherence of actinic light on the primary photochemical charge separation is discussed in some detail.
{"title":"USE OF LASERS IN PHOTOPHYSICAL RESEARCH OF PHOTOSYNTHESIS","authors":"G. Laczkó, P. Maróti, L. Szalay","doi":"10.1155/LC.6.219","DOIUrl":"https://doi.org/10.1155/LC.6.219","url":null,"abstract":"During the past decade, extensive research has been carried out to utilize the unique characteristics of laser light. Mainly the high intensity, short pulse and small divergence of the laser beam have been made use of, and some of the results are briefly summarized here. The effect of the coherence of actinic light on the primary photochemical charge separation is discussed in some detail.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124057095","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}
Photon Echoes in gases are analyzed via the Billiard Ball Echo Model both in the short and long pulse limit where the “atoms” are represented as spherical and elliptical billiard balls, respectively. Recent experiments demonstrating the elliptical billiard ball shape are presented using intensity data which ranges over close to eleven orders of magnitude.
{"title":"Photon Echoes Made Simple","authors":"R. Beach, B. Brody, S. Hartmann","doi":"10.1155/LC.2.3","DOIUrl":"https://doi.org/10.1155/LC.2.3","url":null,"abstract":"Photon Echoes in gases are analyzed via the Billiard Ball Echo Model both in the \u0000short and long pulse limit where the “atoms” are represented as spherical and elliptical \u0000billiard balls, respectively. Recent experiments demonstrating the elliptical billiard ball \u0000shape are presented using intensity data which ranges over close to eleven orders of \u0000magnitude.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126181151","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}
A streptocyanine dye (BMC) and an oxadicarbocyanine (DODCI) were studied in the picosecond and millisecond time region. The comparison showed that for both dyes the following parameters are nearly equal: the radiative lifetime, the difference between the absorption maxima of the stable form and the photoisomer, the activation energy and the frequency factor for the thermal backreaction and even the energy barrier in the excited state.The dyes show strongly different kinetics in the excited state. BMC relaxes faster by about 2 orders of magnitude than DODCI and shows a much higher photoisomerization rate. In accordance with Eyring's theory the higher relaxation and isomerization rate of BMC is connected with an entropy increase in the transition state.
{"title":"Comparison of the photoisomerization and relaxation processes studied by time resolved spectroscopic methods in two polymethine dyes with the same polymethine chromophor","authors":"S. Rentsch, U. Grummt, D. Khetchinashwili","doi":"10.1155/LC.7.261","DOIUrl":"https://doi.org/10.1155/LC.7.261","url":null,"abstract":"A streptocyanine dye (BMC) and an oxadicarbocyanine (DODCI) were studied in the \u0000picosecond and millisecond time region. The comparison showed that for both dyes the \u0000following parameters are nearly equal: the radiative lifetime, the difference between the \u0000absorption maxima of the stable form and the photoisomer, the activation energy and \u0000the frequency factor for the thermal backreaction and even the energy barrier in the \u0000excited state.The dyes show strongly different kinetics in the excited state. BMC relaxes faster by \u0000about 2 orders of magnitude than DODCI and shows a much higher photoisomerization \u0000rate. In accordance with Eyring's theory the higher relaxation and isomerization rate of \u0000BMC is connected with an entropy increase in the transition state.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"183 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124609238","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}
{"title":"The Structure, Function, and Assembly of the Light-Harvesting Antenna of Photosynthetic Purple Bacteria","authors":"R. Grondelle","doi":"10.1155/LC.6.307","DOIUrl":"https://doi.org/10.1155/LC.6.307","url":null,"abstract":"","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124727557","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}
S. Arrivo, V. Kleiman, W. Grubbs, T. P. Dougherty, E. Heilweil
Transient picosecond infrared (IR) spectra of the OH and NH-stretch (v=0–1) absorption bands of several hydrogen-bonded complexes have been investigated. Solutions of 1:1 complexes of weak acids (methanol, triethylsilanol and pyrrole, < 0.1 mol/dm3) and bases (acetonitrile, pyridine and tetrahydrofuran, < 2 mol/dm3) in CCl4 at 295 K were interrogated with IR excitation and broadband probing. Lorentzian-shaped absorption bands are uniformly bleached while those with near-Gaussian bandshapes produce transient spectral holes. These results indicate a base functionality and hydrogen-bond strength dependence for determining the broadening mechanisms of these absorptions.
{"title":"INFRARED SPECTRAL HOLE BURNING OF 1:1 HYDROGEN-BONDED COMPLEXES IN SOLUTION*","authors":"S. Arrivo, V. Kleiman, W. Grubbs, T. P. Dougherty, E. Heilweil","doi":"10.1155/1999/80323","DOIUrl":"https://doi.org/10.1155/1999/80323","url":null,"abstract":"Transient picosecond infrared (IR) spectra of the OH and NH-stretch (v=0–1) absorption bands of several hydrogen-bonded complexes have been investigated. Solutions of 1:1 complexes of weak acids (methanol, triethylsilanol and pyrrole, < 0.1 mol/dm3) and bases (acetonitrile, pyridine and tetrahydrofuran, < 2 mol/dm3) in CCl4 at 295 K were interrogated with IR excitation and broadband probing. Lorentzian-shaped absorption bands are uniformly bleached while those with near-Gaussian bandshapes produce transient spectral holes. These results indicate a base functionality and hydrogen-bond strength dependence for determining the broadening mechanisms of these absorptions.","PeriodicalId":296295,"journal":{"name":"Laser Chemistry","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129446680","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}
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