Showing papers on "Excited state published in 1968"
TL;DR: In this paper, it has been shown that the non-radiative mode excited by light can also radiate under certain conditions if they are excited by electrons (grazing incidence of electrons on a rough surface or at normal incidence on a grating).
Abstract: There are two modes of surface plasma waves: 1) Non-radiative modes with phase velocities Cü/k smaller than the velocity of light c. They cannot decay into photons in general. 2) Radiative modes with (o/k > c which couple directly with photons 1. The following paper is concerned with the excitation of these modes by light and their decay into photons. It has been shown that the radiative mode on thin silverand potassium-films can be excited by light and that the mode reradiates light almost into all directions with an intensity maximum at the plasma frequency cOp 2. It had been further observed that the non-radiative modes radiate under certain conditions if they are excited by electrons (grazing incidence of electrons on . a rough surface3 or at normal incidence on a grating 4) . The mechanism of this emission is in these cases always the same: The \"wave vector\" of the roughness of the surface or its irregularity changes the plasmon wave vector k so that a) in the case of the radiative mode light emission is found in directions in addition to that of reflexion and transmission, b) in the case of the non-radiative mode its wave vector is reduced so that the condition /c0, the wave vector of the inhomogeneous wave is (co/c) • Vsq' sin 0O (fq = 2.16 for quartz) and thus can excite a non radiative mode on the boundary of the prism for j/fq sin 0O > 1 or 90° > @o > 43°. If one vaporises a silver film directly on the quartz surface the inhomogeneous light wave penetrates into the silver film and excites a nonradiative mode on the boundary silver/air. The excitation will be highest for those frequencies which fulfill the dispersion relation of these surface plasmons.
2,790 citations
TL;DR: In this article, the exact solution for a problem of identical two-level molecules interacting through a dipole coupling with a single-mode quantized radiation field at resonance is given, and approximate expressions for the eigenvectors and eigenvalues for the ground and low-lying excited states, as well as the most highly excited states are developed and compared with the exact results.
Abstract: The exact solution for a problem of $N$ identical two-level molecules interacting through a dipole coupling with a single-mode quantized radiation field at resonance is given. Approximate expressions for the eigenvectors and eigenvalues for the ground and low-lying excited states, as well as the most highly excited states, are developed and compared with the exact results.
1,229 citations
TL;DR: In this paper, the authors considered a theory for intramolecular radiationless transitions in an isolated molecule and derived the validity criteria for the occurrence of an unimolecular radii-less transition and for exponential decay.
Abstract: In this paper we consider a theory for intramolecular radiationless transitions in an isolated molecule. The Born–Oppenheimer zero‐order excited states are not pure in view of configuration interaction between nearly degenerate zero‐order states, leading to the broadening of the excited state, the line shape being Lorentzian. The optically excited state can be described in terms of a superposition of molecular eigenstates, and the resulting wavefunction exhibits an exponential nonradiative decay. The linewidth and the radiationless lifetime are expressed in terms of a single molecular parameter, that is the square of the interaction energy between the zero‐order state and the manifold of all vibronic states located within one energy unit around that state. The validity criteria for the occurrence of an unimolecular radiationless transition and for exponential decay in an isolated molecule are derived. Provided that the density of vibrational states is large enough (i.e., exceeds the reciprocal of the interaction matrix element) radiationless transitions are expected to take place. The gross effects of molecular structure on the relevant molecular parameters are discussed.
1,065 citations
TL;DR: In this article, it was shown that if energy is supplied above a certain mean rate to such a branch, then a steady state will be reached in which a single mode of this branch is very strongly excited.
Abstract: Biological systems are expected to have a branch of longitudinal electric modes in a frequency region between 1011 and 1012 sec−1. They are based on the dipolar properties of cell membranes; of certain bonds recurring in giant molecules (such as H bonds) and possibly on pockets of non-localized electrons. In Section 2 it is shown quit generally that if energy is supplied above a certain mean rate to such a branch, then a steady state will be reached in which a single mode of this branch is very strongly excited. The supplied energy is thus not completely thermalized but stored in a highly ordered fashion. This order expresses itself in long-range phase correlations; the phenomenon has considerable similarity with the low-temperature condensation of a Bose gas. General consequences and proposals of experiments are discussed in section 3.
951 citations
TL;DR: In this paper, it was shown that there exists a localized excited state in the energy gap in a superconductor with a classical spin and at finite concentration localized excited states around classical spins form an "impurity band".
Abstract: It is shown that there exists a localized excited state in the energy gap in a superconductor with a classical spin. At finite concentration localized excited states around classical spins form an "impurity band". The process of growth of the "impurity band" and its effects on observable quantities are investigated. § I. Introduction Since the monumental paper by Abrikosov and Gorkov 1 ) many works have been done experimentally and theoretically concerning the thermodynamic and transport properties of superconductors with small amount of paramagnetic impUrItIes. Recently several authors 2 ),3) have been interested in whe'ther loca lized excited states in the energy gap exist in a superconductor with a paramag netic impurity or not. As is well known, a paramagnetic impurity in a normal metal or a superconductor brings about the so-called Kondo effect 4 ) (a kind of quantum mechanical effects of spins) and this makes complete solutions of the problem quite difficult. In this paper we restrict our discussions to the classical spins in supercon ductors. In the s~d interaction between conduction electrons and a localized spin
720 citations
TL;DR: Multiphonon orbit-lattice relaxation of excited states of rare earth ions in crystals, measuring fluorescence lifetimes, quantum efficiencies and transition rates was studied in this paper.
Abstract: Multiphonon orbit-lattice relaxation of excited states of rare earth ions in crystals, measuring fluorescence lifetimes, quantum efficiencies and transition rates
639 citations
TL;DR: In this paper, the modified CNDO method was applied to the calculation of a series of monosubstituted benzenes and pyridines and the calculated values of the transition energies and corresponding oscillator strengths were in good agreement with available experimental data on the electronic spectra of these compounds.
Abstract: The modified CNDO method previously reported has been applied to the calculation of a series of monosubstituted benzenes and pyridines, namely, aniline, anilinium ion, benzonitrile, nitrosobenzene, phenol, phenoxide ion, toluene, pyridinium ion, pyridine‐N‐oxide, 1‐hydroxy‐pyridinium ion, the aminopyridines, and the cyanopyridines. The calculated values of the transition energies and corresponding oscillator strengths are in good agreement with available experimental data on the electronic spectra of these compounds. An analysis of the lower‐energy excited states by means of the calculated results suggests that there is an astonishingly small amount of charge‐transfer character associated with the observed ultraviolet bands. The calculations indicate that the changes in charge densities in going from the ground state to the lowest energy π → π* excited state can be related to the Hammett σ's for the substituents.
333 citations
TL;DR: In this paper, a simple formula permitting a rapid calculation of the total ionisation cross sections as a function of the kinetic energy and mass of the ionizing atom, and of the binding energy and the number of equivalent electrons in the electronic shell to be ionized.
Abstract: Thomson's classical theory for the calculation of ionisation cross sections in electron-atom encounters is applied for calculating the ionisation cross section for atom-atom collisions. A very simple formula is obtained permitting a rapid calculation of the total ionisation cross sections as a function of the kinetic energyEa and the massmA of the ionizing atom, and of the binding energyEi and the number ξi of equivalent electrons in the electronic shell to be ionized. The formula is in good agreement with quantum mechanical calculations and with experimental results. It can be applied to ionization from ground and from excited states. From this formula one obtains an expression for the rate coefficient for ionization in the center-of-mass system of the colliding particles. Then, the method of detailed balancing is applied to calculate the rate coefficient for ion-electron three-body collisional recombination with a neutral atom acting as the third body. This latter formula is applicable to recombination into the ground and into excited states.
293 citations
TL;DR: In this paper, a broad structureless emission band about 5000 cm1 was observed to increase with increasing electron donor concentration at the expense of the fluorescence intensity of the hydrocarbon, thereby following the same Stern-Volmer-type relation as does the well known excimer fluorescence.
Abstract: FLUORESCENCEt Some years ago, while investigating fluorescence quenching of aromatic hydrocarbons (A) by typical electron donors (D), like anilines, we observed1 a broad structureless emission band about 5000 cm1 to the red of the fluorescence of the aromatic hydrocarbon of normal structure. This anomalous fluorescence, as shown in Figure 1, increases in intensity with increasing donor concentration at the expense of the fluorescence intensity of the hydrocarbon, thereby following the same Stern—Volmer-type relation as does the well known excimer fluorescence, e.g. in the case of pyrene2. Extrapolation to infinite donor concentration gives the dashed spectrum (cf. Figure 1) which
282 citations
TL;DR: In this article, the reaction threshold for the reaction producing HeH+, NeH+, and ArH+ in mixtures of hydrogen with rare gases was studied by photoionization mass spectrometry.
Abstract: The reactions producing HeH+, NeH+, and ArH+ in mixtures of hydrogen with rare gases were studied by photoionization mass spectrometry. The HeH+ and NeH+ ions are produced by vibrationally excited H2+ ions; the thresholds for reaction were found to be very near the υ = 3 and υ = 2 states of H2+, respectively. Above the vibrational threshold the reaction cross section increases with vibrational quantum number and there is no evidence for a kinetic‐energy threshold for these states. When accelerated to sufficient kinetic energy, H2+ ions in vibrational states below threshold react with a cross section which increases as the deficit in vibrational energy decreases. The rate constant for reaction of those vibrational states that are near or about the reaction threshold and that contribute most to the observed reaction becomes nearly constant at low repeller voltages. The threshold for the reaction producing HeH+ can be made consistent with a theoretical value for the dissociation energy D0(HeH+) = 1.835 eV. T...
274 citations
TL;DR: In this article, the collision-induced metastability of molecular ions of a number of aromatic compounds has been studied in a double-focusing mass spectrometer, where the ions had been accelerated through a potential difference of 8 kV, they collided with neutral species in the analyzer tube at a pressure of 7 × 10−6 torr.
TL;DR: In this article, the branch of longitudinal electric modes was used for Bose condensation and the excitation energy was channelled into the mode with lowest frequency in a manner typical for BOSE condensation.
TL;DR: In this paper, the authors calculated radiative decay probabilities for electric and magnetic dipole transitions from several electronic states of Pr3+ in LaF3 using the Judd-Ofelt theory and experimental intensity parameters to determine the quantum efficiencies of the 1D2 and 3P0 states.
Abstract: Spontaneous emission probabilities for electric‐ and magnetic‐dipole transitions from several electronic states of Pr3+ in LaF3 are calculated using the Judd–Ofelt theory and experimental intensity parameters. The calculated radiative decay probabilities are combined with observed fluorescence lifetimes to determine the quantum efficiencies of the 1D2 and 3P0 states. Although the lifetimes were measured at low temperatures and small Pr concentrations where competing nonradiative decay by multiphonon emission and ion‐pair relaxation should be negligible, the predicted quantum efficiencies are less than unity. The radiative lifetimes obtained via the Einstein relations and measured integrated absorption and relative fluorescence intensities agree, however, with the observed lifetimes. The discrepancies appear to arise from approximations and possible limitations inherent in the approach used to calculate the radiative transition probabilities. Matrix elements of U(λ) for states of 4f2 in intermediate coupling are included in an appendix.
TL;DR: In this paper, it was shown that band narrowing via intra-atomic exchange is sufficient to localize the d electrons to a cation only if there are at least three unpaired spins at the cation.
TL;DR: In this article, it was shown that the decay rate of the triplet state of naphthalene is linear with the number of deuterons and independent of the position of substitution.
Abstract: The lifetime of the triplet state of aromatic molecules increases when deuterons are substituted for its protons. For naphthalene, our experiments and others show that the decay rate is linear with the number of protons and independent of the position of substitution. This result is shown to follow from Lin's theory of nonradiative decay of excited states.
TL;DR: In this article, an effective nucleon-nucleon interaction of Wigner type V ( r ) = V N exp(− r 2 / γ 2 ) is assumed to induce the scattering.
TL;DR: In this paper, the fraction of excited ions present in an ion beam formed using various energies E8of the electrons in the ion source is determined ∼20 μsec after formation of the ions so that only long-lived states remain in the beam, as is usual in beam experiments.
Abstract: A method has been developed to determine the fraction of excited ions present in an ion beam formed using various energies E8of the electrons in the ion source. The determination is made ∼20 μsec after formation of the ions so that only long‐lived states remain in the beam, as is usual in beam experiments. The method consists of attenuating the ion beam in a gas‐filled reaction chamber, where different states of the ions suffer different attenuations. Results have been obtained for O2+ and O+ ion beams. In each case only one excited state appears to be important: For O2+ the fraction f of this excited state was found to be 0.22, 0.30, and 0.33 for E8 values of 25 eV, 50 eV, and 100 eV, respectively. For O2+, f is 0.27 for E8 = 50 eV and 0.30 for E8 = 100 eV. The use of these results is illustrated by combining them with crossed‐beam measurements of charge transfer to determine separately the cross sections for the ground state and the excited‐state ions of O+ and O2+.
TL;DR: In this paper, the effect of exchange interaction between the ionic moments as it increases from zero towards the critical value necessary for magnetic ordering at zero temperature was studied, and an improved collective-excitation spectrum with a gap which decreases as the exchange increases was obtained.
Abstract: The low-lying magnetic excited states ("Frenkel spin excitons") in rare-earth compounds with a singlet crystal-field ground state are studied. We consider the effect of exchange interaction between the ionic moments as it increases from zero towards the critical value necessary for magnetic ordering at zero temperature. For simplicity, we consider the two-level system where the first-excited crystal-field state is also a singlet. By employing a pseudospin formalism, we avoid many of the fundamental difficulties encountered in previous treatments which introduce fermion operators for each of the crystal-field states. Applying techniques similar to those used in treating standard spin problems such as the Heinsenberg ferromagnet, we obtain an improved collective-excitation spectrum with a gap which decreases as the exchange increases. The critical value of exchange for magnetic ordering found is substantially greater than that obtained from molecular-field theory, and also is somewhat greater than that found with the constant-coupling approximation.
TL;DR: In this article, it was shown that the degree of polarization is related to the form of the anistropy in the angular distribution of dissociation products, and that this form of anisotropic anisomorphism can be used to explain the anomalous behavior of molecular dissociative processes.
Abstract: Fluorescence from excited atomic fragments which arises from molecular dissociative processes can be shown in general to be polarized. The degree of polarization is related to the form of the anistropy in the angular distribution of dissociation products.
TL;DR: In this article, the probability of interaction between two molecules at random at a given distance and undergoing Brownian motion subsequently is determined, and the probability that an A molecule collides with one of many surrounding B molecules is then deduced.
Abstract: The kinetics of diffusion‐controlled chemical reactions in solution are analyzed by a statistical treatment. To start with, the probability of interaction of two molecules A and B, separated by a given distance at zero time and undergoing Brownian motion subsequently, is determined. The probability of interaction of an A molecule with one of many surrounding B molecules is then deduced. Finally, the course of reaction between A and B molecules distributed at random at zero time in a system containing a large number of molecules of both species, is calculated. The treatment outlined is readily extended to systems in which factors other than random diffusion are operative, as well as to systems in which the distribution of A and B molecules is not random at zero time. A few examples are discussed in detail. The theoretical treatment presented is applied to the kinetics of quenching of electronically excited molecules by collision with quencher molecules in solution, and to the calculation of the extent of nonradiative transfer of electronic excitation energy between molecules which are free to undergo Brownian motion.
TL;DR: In this paper, flashlamp-excited polymethyl methacrylate rods containing rhodamine dyes were reported to have light emission in the solid with respect to that observed for the same dyes in liquid solution.
Abstract: Laser emission is reported from flashlamp‐excited polymethyl methacrylate rods containing rhodamine dyes. Quenching of stimulated emission by the molecular triplet state is apparently reduced in the solid with respect to that observed for the same dyes in liquid solution.
TL;DR: In this article, the authors have classified molecules exhibiting vibronic mixing into two extreme cases, which they call the resonant case and the statistical case, characterized by low and high densities of molecular eigenstates, respectively.
Abstract: Radiationless transitions in isolated molecules are examined from the point of view of the breakdown of the Born–Oppenheimer approximation and the nature of the decay of coherently excited states. The problem of intramolecular vibronic coupling between zero‐order Born–Oppenheimer states in an isolated molecule seems amenable now to a new approach both in terms of interpretation and of experimental investigation. We have classified molecules exhibiting vibronic mixing into two extreme cases, which we call the resonant case and the statistical case, characterized by low and high densities of molecular eigenstates, respectively. We have then considered the coherent excitation of these states and derived general expressions for photon counting rates and for the integrated intensity. Quantum beat signals can be investigated to analyze close‐lying molecular eigenstates in the resonance limit. In the statistical limit the interference effects within a manifold of close‐lying states are manifested by a radiationless decay process. An analysis of the radiationless decay times and the quantum yields is given.
TL;DR: In this article, the rotational analysis showed conclusively that the molecule responsible is a diatomic molecule containing two carbon nuclei, a conclusion that was further confirmed by the observation of the corresponding system using 13CH4 instead of 12CH4.
Abstract: A new system of very simple Σ–Σ bands in the region 4800–6000 A has been observed in flash discharges in CH4, both in absorption and emission. The rotational analysis shows conclusively that the molecule responsible is a diatomic molecule containing two carbon nuclei, a conclusion that is further confirmed by the observation of the corresponding system using 13CH4 instead of 12CH4. Neither the upper nor the lower state is one of the known states of C2. None of the predicted low-lying states of C2 fits the observed new states. Two possibilities remain: either the new system corresponds to two fairly highly excited levels of C2 or it is due to the C2− ion. The latter alternative finds some support in the similarity of the new system to the near ultraviolet bands of N2+ (which has the same number of electrons). However, the doublet splitting required by this interpretation has not been resolved, nor has the study of perturbations in the upper state given clear-cut evidence for doublet structure. On the other...
TL;DR: In this article, the authors used the probability of an encounter between a molecule of oxygen and a fluorescent molecule in its excited state, and the energy that would otherwise be emitted as fluorescence is transferred to the oxygen.
Abstract: THE energy acquired by matter when it absorbs electromagnetic radiation is normally converted to heat, but in some cases much of the energy may be re-emitted as fluorescence or phosphorescence. Fluorescence is often quenched (that is, its intensity is reduced) in the presence of oxygen. The degree of quenching depends on the probability of an encounter between a molecule of oxygen and a fluorescent molecule in its excited state, and the energy that would otherwise be emitted as fluorescence is transferred to the oxygen. This effect has been used as the basis of a portable instrument to measure the atmospheric oxygen tension (British Patent Application No. 46674/66). Various prototype devices have been constructed and tested.
TL;DR: In this paper, the phase shift of infrared emission from the asymmetric stretch and from the infrared active bend ν4 has been measured as a function of chopping frequency and gas pressure.
Abstract: The asymmetric stretching vibration ν3 of methane has been excited by a chopped He–Ne laser. The phase shift of infrared emission from the asymmetric stretch and from the infrared‐active bend ν4 has been measured as a function of chopping frequency and gas pressure. Vibrational relaxation times have been found for the removal of energy from the asymmetric stretch (pτ = 7.0 ± 1 nsec·atm), for the appearance of this energy in the ν4 bend (pτ = 5 + 3, −2 nsec·atm), and for the relaxation of vibrational energy into translational and rotational energy (pτ = 1.90 ± 0.10 μsec·atm). The mechanism and rates of V → V energy transfer are compared to calculations for a repulsive intermolecular potential. The general applicability of the laser‐excited vibrational fluorescence method and the interpretation of phase‐shift data are discussed.
TL;DR: In this article, the authors used a correlation diagram connecting planar and twisted molecules to estimate the torsional potential energy curves in ground and excited states of biphenyl and showed that the ground state torsion is a delicate balance of nonbonded repulsion and conjugation.
Abstract: The electronic structure of biphenyl, fulvalene, and related molecules in ground and excited states is studied. To a r-electron SCF and SCF-CI calculation we couple an evaluation of the H-H repulsion to estimate torsional potential energy curves in ground and excited states. The changes in conformational preferences in excited states are easily predicted from a simple correlation diagram connecting planar and twisted molecules. Thus for two coupled q 7r-electron systems one expects planar ground states, possibly twisted excited states, for q = 4n + 1 or 4n + 3 ; planar ground or excited states, possibly triplet or quintet ground states, for q = 4n; possibly twisted ground states and planar excited states for q = 4n + 2. he molecule of biphenyl is planar or nearly so in T the solid state,’V2 twisted some 40” around the central single bond in the vapor phasei3 The groundstate torsion is thus clearly a delicate balance of nonbonded repulsion and conjugation, and the groundstate rotational potential has attracted some theoretical attention. 4-6 There have been a number of calculations directed toward explicating the spectrum of biphenyl.’-I3 These calculations probe only the ground-state geometry, and generally good agreement with experiment is obtained for twist angles correlating well with the vaporphase equilibrium geometry. That the inter-ring bond acquires some double-bond character in the lowest excited state of the molecule is an obvious conclusion from either a ~a lence-bond’~ or molecular-orbitalI5 viewpoint. The influence of this potential energy change on the position and intensity of electronic transitions has been ably discussed by Jaffd and Orchin. Recently, some stimulating experiments were reported by Wagner.I6 From a study of the singlet-triplet absorption, its quenching, and the phosphorescence of biphenyl, it was concluded that in its lowest excited triplet biphenyl was planar, in contrast to its twisted ground-state equilibrium conformation. (1) J. Trotter, Acta Cryst . , 14, 1135 (1961); A. Hargreaves and S. H. (2) G. B. Robertson, Nature, 191, 593 (1961). (3) A. Almenningen and 0. Bastiansen, Kgl. Danske Norske Videnskab Selskab Skrifter, No. 4 (1958); 0. Bastiansen, Acta Chem. Scand. 4, 926 (1950). (4) S. Samoilov and M. Dyatkina, Zh. Fiz. Khim., 22, 1294 (1948). (5) F. J. Adrian, J . Chem. Phys. , 28, 608 (1958). (6) I. Fischer-Hjalmars, Tetrahedron, 19, 1805 (1963). (7) A. London, J . Chem. Phys. , 13, 393 (1945); E. T. Stewart, J . (8) H . C. Longuet-Higgins and J. N. Murrell, Proc. Phys. SOC. (Lon(9) K. Iguchi, J . Phys. SOC. Japan, 12, 1250 (1957). (10) H . Suzuki, Bull. Chem. SOC. Japan, 32, 1340 (1959); H. Suzuki, “Electronic Absorption Spectra and Geometry of Organic Molecules,” Academic Press, New York, N. Y., 1967, p 262. (11) Y. Gondo, J . Chem. Phys., 41, 3928 (1964). (12) R. Grinter, Mol. Phys., 11, 7 (1966). (13) A. Golebiewski and A. Parczewski, Theoret. Chim. Acta, 7, 171 (14) G. N. Lewis and M. Kasha, J . Am. Chem. SOC., 66, 2100 (1944). (15),(a) H. H. Jaffe an; M. Orchin, “Theory and Applications of Ultraviolet Spectroscopy, John Wiley and Sons, Inc., New York, N. Y., 1962, p 389; (b) H. H. Jaffk and M. Orchin, J . Chem. Soc., 1078 (1960). Rizvi, ibid., 15, 365 (1962). Chem. SOC., 4016 (1958). don), A68, 601 (1955).
TL;DR: In this paper, a new method for the determination of diffusion coefficients for hydrogen and deuterium in niobium was proposed, where the activation energy for hydrogen diffusion is equal to the energy difference between the ground state and the first excited state of the hydrogen atom in solution.
Abstract: We have applied a new method for the determination of diffusion coefficients to hydrogen and deuterium in niobium. The activation energies for both isotopes are comparatively small and differ by about 20%, whereas ${D}_{0}$ is the same within experimental error. The activation energy for hydrogen diffusion is equal to the energy difference $\ensuremath{\hbar}{\ensuremath{\omega}}_{\mathrm{H}}=114\ifmmode\pm\else\textpm\fi{}6$ meV between the ground state and the first excited state of the hydrogen atom in solution.
TL;DR: In this paper, a series of calculations on the excited states of formaldehyde using excitation operator techniques are presented, and the results are in moderate agreement with experiment; a major source of error probably arises from the use of an unoptimized, minimum basis set LCAO(STO)-MO-SCF wavefunction.
Abstract: A series of calculations on the excited states of formaldehyde using excitation operator techniques are presented. As in ethylene, the effect of sigma–pi interaction on the "pi-->pi*"(1A1) excitation is rather large, decreasing the calculated excitation energy from 14.89 to 12.03 eV and the oscillator strength from 1.01 to 0.30. The coupling has little effect on the corresponding triplet state (3A1). The next higher approximation reduces the excitation energy to 11.22 eV and the oscillator strength to 0.21. The effect of the coupling on the "n-->pi*"(1,3A2) excitations is not as large as that for the 1A1 state, lowering the excitation energies for both the singlet and triplet by ~0.5 eV. Similar results were obtained for the "sigma-->pi*"(1,3B1) excitations. Trends are observed in calculations on corresponding states in ethylene and formaldehyde. Numerous one-electron properties are calculated for the excited states. The results are in moderate agreement with experiment; a major source of error probably arises from the use of an unoptimized, minimum basis set LCAO(STO)–MO–SCF wavefunction.
TL;DR: In this paper, the interaction between a fast incident electron and a metallic spherical particle full of a free electron gas as the conduction electrons using the hydrodynamic equations of Bloch is studied.
Abstract: The interactions between a fast incident electron and a metallic spherical particle full of a free electron gas as the conduction electrons are studied using the hydrodynamic equations of Bloch. The obtained energy spectrum of a transmitted electron is composed of the well known peak due to the bulk plasma oscillations with small corrections and the peak due to the surface plasma oscillations which are given by sum of various modes of oscillations with different energies. The energy value of the surface oscillations at maximum intensity increases with increasing particle size and tends to that in the foil case. Numerical examples are given for aluminum particle coated with aluminum oxide and for colloidal alkali metal in alkali halide. The latter example is compared with experimental observations. The possibility of the plasma radiation is also discussed. The radiated photon energy is the same as that in the Mie scattering from small particle. Energy spectrum, angular distribution and photon yield are num...
TL;DR: In this article, the Onsager model of dielectrics is applied to the analysis of solvent shifts of absorption bands and correlations with various solvent properties, such as dipole moments and polarizabilities of excited states.
Abstract: Experimental observations about solvent shifts of absorption bands are reviewed, and correlations with various solvent properties are discussed. The theory is treated according to the Onsager model of dielectrics which shows how data like dipole moments and polarizabilities of excited states can be obtained from solvent-shift experiments. Shifts resulting from dispersion interaction and from specific solvent–solute interaction, in particular hydrogen bonding, are considered. Possible improvements in the theory of solvent shifts are briefly discussed.