{"title":"Introduction to modern vibrational spectroscopy","authors":"H.G.M. Edwards","doi":"10.1016/0584-8539(94)80073-1","DOIUrl":"10.1016/0584-8539(94)80073-1","url":null,"abstract":"","PeriodicalId":82782,"journal":{"name":"Spectrochimica acta. Part A: Molecular spectroscopy","volume":"50 14","pages":"Pages 2397-2398"},"PeriodicalIF":0.0,"publicationDate":"1994-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0584-8539(94)80073-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"98110354","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}
P.V. Lalitha, R. Ramaswamy, Geetha Ramakrishnan, P.Sambasiva Rao
{"title":"Study of Belousov—Zhabotinsky oscillators in water—acetonitrile medium employing EMF and EPR techniques with o-vanillin, p-vanillin and adrenaline as substrates","authors":"P.V. Lalitha, R. Ramaswamy, Geetha Ramakrishnan, P.Sambasiva Rao","doi":"10.1016/0584-8539(94)E0008-X","DOIUrl":"10.1016/0584-8539(94)E0008-X","url":null,"abstract":"<div><p>The oscillatory behaviour of three substrates, <em>ortho</em>-vanillin, <em>para</em>-vanillin and adrenaline, in mixed media (water plus 20% acetonitrile) has been investigated using EPR and EMF techniques. All these substrates exhibit two types of oscillation involving Br<sub>2</sub>/Br<sup>−</sup> and Mn(III)/Mn(II) redox couples. From the oscillatory characteristics (total time, number of oscillations and time per oscillation) obtained by employing these techniques, the reactivities of the vanillins have been correlated. The Field—Koros—Noyes mechanism, suggested for catalysed systems in pure aqueous medium, is established to be applicable even in mixed media.</p></div>","PeriodicalId":82782,"journal":{"name":"Spectrochimica acta. Part A: Molecular spectroscopy","volume":"50 14","pages":"Pages 2345-2353"},"PeriodicalIF":0.0,"publicationDate":"1994-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0584-8539(94)E0008-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76718820","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}
Oleg N. Ulenikov , Assia B. Malikova , Hua-feng Li, Hai-bo Qian, Qing-shi Zhu, B.A. Thrush
{"title":"High resolution study of the ν1+ν2 and ν2+ν3 vibration—rotation bands of H2Se","authors":"Oleg N. Ulenikov , Assia B. Malikova , Hua-feng Li, Hai-bo Qian, Qing-shi Zhu, B.A. Thrush","doi":"10.1016/0584-8539(94)E0002-R","DOIUrl":"10.1016/0584-8539(94)E0002-R","url":null,"abstract":"<div><p>High resolution spectra of H<sub>2</sub>Se ν<sub>1</sub>+ν<sub>2</sub> and ν<sub>2</sub>+ν<sub>3</sub> bands have been recorded and analysed in natural isotopic abundance. The vibration—rotation transitions of H<sub>2</sub><em><sup>n</sup></em>Se (<em>n</em> = 82, 80, 78, 77, 76 and 74) are assigned by using ground state combination differences and are least-squares fitted to give rise to the vibration—rotation parameters. The isotope effect is discussed.</p></div>","PeriodicalId":82782,"journal":{"name":"Spectrochimica acta. Part A: Molecular spectroscopy","volume":"50 14","pages":"Pages 2371-2383"},"PeriodicalIF":0.0,"publicationDate":"1994-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0584-8539(94)E0002-R","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88927559","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}
G.Lokeswara Reddy, C. Santhamma, G.S.P.B. Lakshmi, N. Dhananjava, Y.L.N. Murthy, A.S.R. Anjaneyulu, V.K. Mago, A.K. Ray, B. Lal
{"title":"Spectroscopic and lasing characteristics of 7-N,N-diallylamino(-3-aryl)-coumarins and 2-pyrazolines—a new class of potential laser dyes","authors":"G.Lokeswara Reddy, C. Santhamma, G.S.P.B. Lakshmi, N. Dhananjava, Y.L.N. Murthy, A.S.R. Anjaneyulu, V.K. Mago, A.K. Ray, B. Lal","doi":"10.1016/0584-8539(94)E0018-6","DOIUrl":"10.1016/0584-8539(94)E0018-6","url":null,"abstract":"<div><p>The near UV absorption spectra and fluorescence spectra of new coumarin dyes and pyrazolines synthesized in our laboratories are investigated in solution. The effects of solvent and pH factor on the absorption and fluorescence maxima are also studied. The fluorescence lifetimes of coumarins are determined in different solvents. The regression relations for the absorption maxima, fluorescence maxima and fluorescence lifetimes as a function of polarity, refractive index and dielectric constant of the solvent are derived. The lasing maximum peak and range are determined for four of the new coumarins using the Nitrogen Pulsed Dye Laser at L and PT Division, BARC, Bombay. All the dyes investigated are of purity > 99% as determined by high performance liquid chromatography (HPLC). The NMR, mass and IR spectra are recorded for examining the structures. All dyes tested for lasing characteristics are found to be good laser dyes in the blue—green region.</p></div>","PeriodicalId":82782,"journal":{"name":"Spectrochimica acta. Part A: Molecular spectroscopy","volume":"50 14","pages":"Pages 2311-2326"},"PeriodicalIF":0.0,"publicationDate":"1994-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0584-8539(94)E0018-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74533613","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":"Carbon-13 NMR studies of oxo-centered trinuclear chromium(III) complexes of the general formula [Cr3O(O2CR)6(L)3]+ (R = Me, Ph; L = H2O, py)","authors":"K. Belmore, X.J. Madison, A. Harton, J.B. Vincent","doi":"10.1016/0584-8539(94)E0003-S","DOIUrl":"10.1016/0584-8539(94)E0003-S","url":null,"abstract":"<div><p><sup>13</sup>C NMR resonances of a series of oxo-centered trinuclear chromium complexes have been observed and assigned. A π-delocalization mechanism dominates where ligands contain aromatic substituents or bridging carboxylate functionalities, consistent with the presence of a metal center where to first approximation unpaired electrons reside solely in <em>t</em><sub>2g</sub>. orbitals. A contrast is made between the delocalization mechanism in these complexes and those of their isostructural Mn and Fe analogues.</p></div>","PeriodicalId":82782,"journal":{"name":"Spectrochimica acta. Part A: Molecular spectroscopy","volume":"50 14","pages":"Pages 2365-2370"},"PeriodicalIF":0.0,"publicationDate":"1994-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0584-8539(94)E0003-S","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74189588","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":"Ground state vibrations of citric acid and the citrate trianion—an ab initio study","authors":"P. Tarakeshwar, S. Manogaran","doi":"10.1016/0584-8539(94)E0017-5","DOIUrl":"10.1016/0584-8539(94)E0017-5","url":null,"abstract":"<div><p><em>Ab initio</em> force fields for the vibrations of citric acid and citrate trianion in their ground electronic states have been determined at the Hartree—Fock level using the 4–21G basis set. The calculated geometries have been compared to the corresponding X-ray structures of citric acid and magnesium citrate, respectively. The calculated vibrational frequencies have been used to assign the experimental IR and Raman spectra of citric acid and sodium citrate. The calculated potential energy distribution, Raman activities and IR intensities have been used as aids in the assignment of the vibrational spectra of citric acid and sodium citrate.</p></div>","PeriodicalId":82782,"journal":{"name":"Spectrochimica acta. Part A: Molecular spectroscopy","volume":"50 14","pages":"Pages 2327-2343"},"PeriodicalIF":0.0,"publicationDate":"1994-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0584-8539(94)E0017-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81834323","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":"Surface enhanced Raman spectra of isomeric acetylpyridines adsorbed on silver sol","authors":"Kana M. Mukherjee, U.K. Sarker, T.N. Misra","doi":"10.1016/0584-8539(94)E0004-T","DOIUrl":"10.1016/0584-8539(94)E0004-T","url":null,"abstract":"<div><p>Raman spectra of 2-, 3- and 4-acetylpyridines (AP) are obtained in bulk phase, in aqueous solution and in the adsorbed state on colloidal silver particles. Addition of the acetylpyridines on the Ag-sol results in aggregation of the silver particles showing characteristic charge transfer (CT) bands. Significant surface enhancement of the Raman bands are observed. Both the estimated enhancement factor and the absorption maxima of the CT bands are in inverse parallel relationship with the electron density on the nitrogen atom as reflected by the Hammett σ values of the substituents. It is inferred that the charge transfer interactions between the adsorbates and the metal particles contribute to the enhancement mechanism. This is further substantiated by the concentration dependence of enhancement. A classical electromagnetic contribution is demonstrated by the Raman excitation frequency dependence of SERS. The results further show that the molecules are adsorbed on the metal surface through the nitrogen atom. Appearance of some out-of-plane modes in the SERS spectra suggests that the pyridyl ring planes are not perpendicular to the metal surface, but are tilted.</p></div>","PeriodicalId":82782,"journal":{"name":"Spectrochimica acta. Part A: Molecular spectroscopy","volume":"50 14","pages":"Pages 2355-2363"},"PeriodicalIF":0.0,"publicationDate":"1994-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0584-8539(94)E0004-T","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85900482","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":"Vibrational and electronic spectra of copper(II) chromate","authors":"Enrique J. Baran","doi":"10.1016/0584-8539(94)E0001-Q","DOIUrl":"10.1016/0584-8539(94)E0001-Q","url":null,"abstract":"<div><p>The infrared, Raman and electronic (reflectance) spectra of CuCrO<sub>4</sub> were recorded. The internal vibrations of the CrO<sup>2−</sup><sub>4</sub> ions were assigned with the aid of a factor group analysis. The ‘<em>d-d</em>’ transitions of the Cu<sup>II</sup>O<sub>6</sub> moieties and one of the O → Cu charge transfer bands could also be assigned. Some comparisons with other structurally related compounds are made.</p></div>","PeriodicalId":82782,"journal":{"name":"Spectrochimica acta. Part A: Molecular spectroscopy","volume":"50 14","pages":"Pages 2385-2389"},"PeriodicalIF":0.0,"publicationDate":"1994-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0584-8539(94)E0001-Q","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76273902","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}