Quasilinear Spectra Research Articles

ChemInform Abstract: Low‐Temperature Spectroscopy of Organic Molecules in Solid Matrices: From the Shpol′skii Effect to Laser Luminescent Spectromicroscopy for All Effectively Emitting Single Molecules

AbstractReview: 175 refs.

Low-temperature spectroscopy of organic molecules in solid matrices: from the Shpol'skii effect to laser luminescent spectromicroscopy for all effectively emitting single molecules

Sixty years ago, in 1952, Prof. E V Shpol'skii and his colleagues were the first to see quasilinear spectra from complex organic compounds in specially selected solvents at low temperatures. Twenty years later, in 1972, a team headed by Prof. R I Personov discovered laser fluorescence line narrowing in the solid solutions of organic dyes. These two discoveries served as the basis for the field of laser selective spectroscopy of impurity centers in solids. The work in this field culminated in the techniques of spectroscopy and luminescence imaging (microscopy) of single molecules in condensed matter. Today, optical spectroscopy of impurity centers in solid solutions has become one of the most popular tools for solving a wide variety of interdisciplinary problems in physics, physical chemistry, optics and spectroscopy, biophysics, quantum optics, and nanotechnology. In this article, the development of this field is briefly reviewed, potentials of the developed methods are discussed, and some research results are highlighted.

Simulation of shoreline change using AIRSAR and POLSAR C-band data

This paper presents a new approach for modeling shoreline change due to wave energy effects from remotely sensed data. The airborne AIRSAR and POLSAR data were employed to extract wave spectra information and integrate them with historical remotely sensed data such as aerial photography data to model the rate of change of the shoreline. A partial differential equation (PDE) of the wave conversion model was applied to investigate the wave refraction patterns. The volume of sediment transport at several locations was estimated based on the wave refraction patterns. The shoreline change model developed was designed to cover a 14-km stretch of shoreline of Kuala Terengganu in Peninsular Malaysia. The model utilized data from aerial photographs, AIRSAR, POLSAR, ERS-2, and in situ wave data. The results show that the shoreline rate of change modeled from the quasi-linear wave spectra algorithm has a significant relationship with one estimated from historical vector layers of aerial photography, AIRSAR, and POLSAR data. With the quasi-linear algorithm, an error of ±0.18 m/year in shoreline rate of change determination was obtained with Cvv band.

Luminescent Determination of Automobile Petrol in Hexane Solutions

The work deals with the problem of determination of automobile petrol of various octane numbers and petroleum contamination of some objects on the basis of analysis of photoluminescence spectra of automobile petrol samples. For this purpose steady state luminescence properties of samples of automobile petrol of different types being in sale were measured. Samples of automobile petrol diluted in hexane were prepared and their luminescence spectra were measured at room and liquid nitrogen temperatures of samples. We constructed concentration dependences of luminescence intensity of both wide band luminescence of liquid solutions obtained at room temperature and peak intensities of luminescence lines of quasi linear spectra of solutions frozen at 77 K. Possibility to use luminescence method for analysis of petrol pollutions on some objects is illustrated by results of investigation of pine-wood pieces contaminated by automobile petrol.

Content of 3,4-Benzopyrene in Sediments of Lake Ladoga, Neva River and Eastern Gulf of Finland System

Abstract In 1993-94, sediment samples of the aquatic system comprising Lake Ladoga, the Neva River and the Eastern Gulf of Finland were collected to determine the content of 3,4-benzopyrene (3,4-PB) as an indicator of polycyclic aromatic hydrocarbons in the environment. Two methods were used: (1) microspectrofluorom-etry with quasi-linear spectra fluorescence and (2) high-performance liquid chromatography. Results show the heterogeneous distribution of 3,4-benzopyrene in the sediments. The highest concentrations (20 to 100 µg kg−1) were found in Lake Ladoga, near urban areas, and in the Neva River, near industrial compounds. High concentrations were also detected in the central part of Neva Bay and near a resort in the Gulf of Finland.

Isolation and fingerprinting of some high-molecular-weight polynuclear aromatic compounds

The high-molecular-weight polynuclear aromatic hydrocarbon (PAC) fraction of a carbon black extract was isolated with a backflush technique, and applied to an amino-bonded stationary phase for HPLC. This fraction was further separated into 44 sub-fractions by means of reversed-phase HPLC, on an ODS column. Low-temperature fluorescence, utilizing the Shpol'skii effect, was then applied to each fraction. By this method, quasilinear spectra were recorded from mostly peri- condensed PACs with molecular weights up to 400 daltons. Nine compounds with molecular weights exceeding 300 daltons were identified.

Sensitive luminescence analysis for inorganic ions

Use of excitation by powerful monochromatic light sources (including lasers) and of selective quasilinear radiation spectra of organoluminophores in metal complexes in non-aqueous media is proposed for more efficient luminescence analysis of inorganic substances.

Diffusion acoustique par des tubes immergés. origine d'une famille de résonances

The experimental method described for the first time by Maze, Taconet and Ripoche and now called “method of isolation and identification of resonances” (MIIR) has been applied to the study of cylindrical targets immersed in water. It allows the isolation of resonances in quasilinear spectra and their identification. An analysis of the “resonance spectra” shows that some lines do not belong to series supplied by the theory when the calculation is made with a plane acoustic wave which has its wave vector perpendicular to the axis of the target. The origin of a series of lines is determined by studying the guided propagation along the axis of the cylindrical shells.

Highly resolved optical spectra of a 2,3-naphthoquinodimethane derivative in a Shpol'skii matrix

The Shpol'skii method yields quasilinear spectra of exo-naphtho [b:3,4] tricyclo [4.2.1.0. 2,5] nonane 5 in n-hexane at 5 K. This result is discussed with reference to the “key and hole” rule. Highly resolved spectra of the 2,3-naphthoquinodimethane derivative 4 are obtained by photolysis of 5. The results are comparable with those of o-durylene 3.

Vibronic coupling effects in the highly resolved optical spectra of 1,3-perinaphthadiyl, a molecule with a triplet ground state

Quasilinear spectra of 1,3-perinaphthadiyl have been obtained in n-pentane and n-hexane by photolysis of cyclopropanoacenaphthylene. The spectra of the biradical display a large absorption-emission asymmetry, which is discussed in terms of vibronic coupling. Our analysis indicates that the two lowest excited electronic states are separated by less than 250cm −1. The results of open shell PPP and CNDO/S calculations with various CI bases are given and compared with experimental data.

Spectroscopic investigations of photolysis products of organic compounds in Shpolskii matrices. Application to acenaphthene and monomethylnaphthalenes

It is shown that Shpolskii matrices can be very suitable to acquire quasilinear spectra of trapped unstable species. Photolysis of acenaphthene and monomethylnaphthalenes in Shpolskii matrices yields photoproducts exhibiting highly resolved spectra. It is proposed that in addition to the acenaphthenyl radical the 1-acenaphthenium cation is formed, whereas photolysis of monomethylnaphthalenes produces the methylnaphthyl radicals, the methylnaphthenium cations and the benzocycloheptenium cation.

High-resolution electronic spectra and luminescence properties of some benzonaphthyridines at 77 K. absorption and fluorescence spectra of 1,5-, 1,6- a

Absorption and fluorescence spectra of 1,5-, 1,6- and 4,6-benzo[h]naphthyridines (BN) were examined in Shpolskii matrices and in n-butanol at 77 K. Vibrational analysis of quasilinear spectra of 1,6- and 4,6-BN in n-hexane matrices was performed. Calcula- tions of the electronic structure of the isomers examined were done using a modified INDO CI method. The results of the experiments and calculations prove the π, π * state to be the lowest excited singlet state of 1,6- and 4,6-BN molecules; in 1,5-BN molecule the S 1 (n, π *) state is strongly perturbed by the nearby s 2(π π *) state.

Levels of benzo(a)pyrene in oil shale industry wastes, some bodies of water in the Estonian S.S.R. and in water organisms.

Data on the content of benzo(a)pyrene (BP) in oil shale industry wastewater, the effectiveness of various effluent treatment processes (evaporation, extraction with butyl acetate, trickling filters, aeration tanks) in reducing the level of BP in oil shale wastewater, the level of BP in various bodies of water of Estonia, and in fish and other water organisms are reviewed. The quantitative determination of BP in concentrated diethyl ether extracts of water samples was carried out by ultraviolet and spectroluminescence procedures by use of the quasi-linear spectra at -196 degrees C in solid paraffins. It has been found that oil shale industry wastewater contains large amounts of BP. The most efficient purification process for removing the BP in oil shale industry phenol water is extraction with butyl acetate. The level of BP in the rivers of the oil shale industry area is comparatively higher than in other bodies of water of the Republic. The concentration of BP in the lakes of the Estonian S.S.R. is on the whole insignificant. Even the maximum concentration found in our lakes is as a rule less than the safety limit for BP in bodies of water (0.005 microgram/l). During water is treated at the waterworks. The effectiveness of the water treatment in reducing the level of BP varies from 11 to 88%. Filtration was found to be the most effective treatment. About 20 samples of fish from nine bodies of water in Estonia have been analyzed for content of BP. The average content of BP in the muscular tissue of various species of fish is as a rule less than 1 microgram/kg. There is no significant difference in the concentration of BP in sea and freshwater fish. There is no important difference in the content of BP in the organs of various fish. Fat fish contain more BP than lean ones. The weight (age) of fish does not influence the content of BP in the muscular tissue of fish.

Levels of Benzo(a)pyrene in Oil Shale Industry Wastes, Some Bodies of Water in the Estonian S.S.R. and in Water Organisms

Data on the content of benzo(a)pyrene (BP) in oil shale industry wastewater, the effectiveness of various effluent treatment processes (evaporation, extraction with butyl acetate, trickling filters, aeration tanks) in reducing the level of BP in oil shale wastewater, the level of BP in various bodies of water of Estonia, and in fish and other water organisms are reviewed. The quantitative determination of BP in concentrated diethyl ether extracts of water samples was carried out by ultraviolet and spectroluminescence procedures by use of the quasi-linear spectra at -196 degrees C in solid paraffins. It has been found that oil shale industry wastewater contains large amounts of BP. The most efficient purification process for removing the BP in oil shale industry phenol water is extraction with butyl acetate. The level of BP in the rivers of the oil shale industry area is comparatively higher than in other bodies of water of the Republic. The concentration of BP in the lakes of the Estonian S.S.R. is on the whole insignificant. Even the maximum concentration found in our lakes is as a rule less than the safety limit for BP in bodies of water (0.005 microgram/l). During water is treated at the waterworks. The effectiveness of the water treatment in reducing the level of BP varies from 11 to 88%. Filtration was found to be the most effective treatment. About 20 samples of fish from nine bodies of water in Estonia have been analyzed for content of BP. The average content of BP in the muscular tissue of various species of fish is as a rule less than 1 microgram/kg. There is no significant difference in the concentration of BP in sea and freshwater fish. There is no important difference in the content of BP in the organs of various fish. Fat fish contain more BP than lean ones. The weight (age) of fish does not influence the content of BP in the muscular tissue of fish.

Absorption and Fluorescence Spectra of some 1,3,4-Oxadiazole Derivatives in n-Paraffins at 77 K

Abstract The quasilinear absorption and fluorescence spectra of 2- (1-naphthyl) -5-phenyl 1,3,4 oxadiazole, 2-(2-naphthyl)-5- phenyl 1,3,4 oxadiazole, 2-(1-naphthyl) -5-(4-biphenylyl) - 1,3,4 oxadiazole and 2-(2-naphthyl)-5-(4-biphenylyl)-1,3,4 oxadiazole have been studied in n-hexane, decane and nonane at 77 K. An analysis of the vibrational structure in the first electronic excited singlet state (S1) and in the ground state (S0) is given. Internal oscillations in the investigated molecules found from the quasilinear spectra are in agreement with those found in the infrared spectra.

Quasilinear spectra of ?double? molecules with weak resonance bonds

Quasilinear spectra of ?double? molecules with weak resonance bonds

On the Absorption Spectrum of Isoquinoline and 3-Mcthylisoquinoline in Tetrahydrofuran and n-Paraffin

Abstract The quasilinear absorption spectra of isoquinoline and 3-methylisoquinoline have been studied in tetrahydrofuran and n-paraffin solvents at 77 °K. An analysis of the vibrational structure in the first electronic excited singlet state (S1 is given. Different multiplicities of the absorption spectra have been studied and explained.

High resolution spectroscopy of the electronic excitation of NO trapped in rare gas matrices: The B2Π ← X2Π system

The high resolution (0.014 Å in the range 2000-1500 Å) investigation of quasilinear spectra observed with NO in Ne or Ar matrices below 2000 Å provides useful information about various types of interactions of the molecule with the host crystal. Some features obtained are discussed in terms of a static interaction which leads to the washing out of the Rydberg transitions. The dynamic interaction is revealed through spectral features which reflect the phonon density of states of the matrix as well as through features correlated to libration in the site.

Spectres de fluorescence de radicaux produits par photodissociation des éthyltoluènes piégés dans des matrices cristallines à très basse température

The fluorescence spectra of radicals from o-, m, and p-ethyltoluenes have been examined at 9° K. The radicals are trapped in crystalline matrixes of methyl-cyclohexane and methylcyclopentane. Quasi-linear spectra were obtained for radicals from o- and m-ethyltoluenes. A vibrational analysis of some spectra is proposed and fundamental frequencies are assigned.

Line-profiles in teh quasilinear spectra of organic molecules in n-paraffin solid solutions

From the Weisskopf—Wigner formula a line-profile is obtained which describes quasilinear spectral bands when the background to the ‘phononless’ line is considered. Preliminary comparisons are made with experimental evidence on the temperature dependence of quasilines.