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1.
The band shapes in the absorption spectra of dimers of cyanine dyes were simulated using a combination of an empirical molecular force field for the ground state with quantum-chemical calculations of the electron excitation energy as a function of normal nuclear coordinates. The shape and the width of an absorption band strongly depend on the mutual arrangement of the monomers. If the monomers are located one directly above the other, the sublevels arising from intramolecular vibrations disappear in the spectrum, and a large hypsochromic shift of the 0-0-transition band is observed, which results mainly from through-space interaction of monomer orbitals. If the monomers are strongly shifted relative to each other, the sublevels mentioned are also absent in the spectrum, but the bathochromic shift of the 0-0-transition band is small and results from interaction of dipole moments of electron transitions. A rather broad region of intermediate structures is found between these dimer forms, where the interaction of dipole moments of electron transitions in monomers is low, and the shapes of absorption bands are similar to those of the monomers.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1705–1710, September, 1995.This work was financially supported by the Russian Foundation for Basic Research (Project No. 94-03-08539) and the International Science Foundation (Grant M1Z 000). 相似文献
2.
The formation ofJ-aggregates of three polymethine dyes in solutions and in Langmuir-Blodgett (LB) polylayers was studied. The dyes formJ-aggregates in mixtures of solvents of different polarity: hexane-chloroform and heptane-chloroform taken in various ratios. The formation ofJ-aggregates in LB polylayers depends on the type of matrix and on the matrix: dye ratio.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 96–99, January, 1995.The authors are grateful to Corresponding Member of the Russian Academy of Sciences M. V. Alfimov for valuable remarks and to Dr. A. I. Tolmachev for kindly donating samples of dyes.This work was financially supported by the Russian Foundation for Basic Research (Project No. 94-03-09182). 相似文献
3.
N. A. Davidenko N. A. Derevyanko A. A. Ishchenko S. L. Studzinskii 《Theoretical and Experimental Chemistry》2008,44(6):351-355
We have observed that in an external d.c. electric field, in the differential fluorescence spectra of both symmetric and asymmetric
polymethine dyes in a polymer film, the intensity of the emission in the long-wavelength region of the band increases while
the intensity in the short-wavelength region decreases. In symmetric polymethines, these effects are opposite to those in
the differential absorption spectra, while in asymmetric polymethines they are symbatic. The spectral effects were interpreted
by a change in the probability of the vibronic transitions due to redistribution of electron density in the chromophore, in
the ground state and the excited state of the dye, in an external electric field.
Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 44, No. 6, pp. 343–347, November–December, 2008. 相似文献
4.
Yuexing Zhang Xue Cai Xianxi Zhang Hui Xu Zhongqiang Liu Jianzhuang Jiang 《International journal of quantum chemistry》2007,107(4):952-961
Time‐dependent density functional theory (TD‐DFT) calculations were carried out in a comparative study of the electronic absorption spectra of lead(II) phthalocyaninate (PbPc), tin(II) phthalocyaninate (SnPc), tin(IV) dichlorophalocyaninate (PcSnCl2), germanium(II) phthalocyaninate (GePc), and germanium (IV) dichlorophalocyaninate (PcGeCl2) with the B3LYP method and LANL2DZ basis set. Our calculated bands correspond well with the experimental results. The electronic natures of all the bands in the absorption spectra are assigned and analyzed comparatively according to the calculated electronic transition contributions. With the increase of the dielectric constant from CHCl3 to DMSO, all the electronic absorption bands are somewhat red shift, consistent with the shift rules measured experimentally. The radius of the central metals has great influence to the absorption spectra, especially for the B bands. The influence of the radius of the central metals to the absorption spectra of PcSnCl2 and PcGeCl2 is smaller than to the spectra of the nonplanar MPcs (M = Pb, Sn, and Ge). Axial ligands also greatly changed the electronic absorption spectra due to the change of the orbital energy level and the molecular symmetry. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 相似文献
5.
V. I. Baranovski E. N. Pisarevskaya O. V. Vinogradova O. V. Sverdlova I. A. Balova 《Russian Chemical Bulletin》2007,56(10):2014-2020
The results of experimental and theoretical investigation of the electronic absorption spectra of substituted phenyldiacethylenes
are presented. The bands in the experimental spectra were assigned in detail using quantum chemical calculations of the electronic
structures and spectra of the molecules. The influence of the interaction of the substituents on the spectral parameters of
the systems under study was analyzed.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1947–1953, October, 2007. 相似文献
6.
S. Yu. Ketkov G. A. Domrachev C. P. Mehnert J. C. Green 《Russian Chemical Bulletin》1998,47(5):868-874
The effect of methylation of ligands in bis(η6-benzene)chromium (1) on the structure of Rydberg transitions in absorption spectra has been studied. A detailed analysis
and interpretation of all Rydberg elements of the vapor-phase spectra of bis(η6-benzene)chromium (2), bis(η6-o-xylene)chromium (3), bis(η6-m-xylene)chromium (4), and bis(η6-mesitylene)chromium (5) was carried out. The vapor-phase electronic absorption spectrum of bis(η6-p-xylene)chromium (6) was measured, and the assignment of the Rydberg bands was made for the first time. The first ionization
potentials of complexes 2–5 were refined. The energy of detachment of the 3dz
2 electron and the parameters of the Rydberg excitations for molecule 6 were determined. The vibronic components of the 3dz
2→R4p
x,y
transition in the spectra of complexes 2 and 6 were assigned. The differences in the Rydberg structure of the spectra of
compounds 2–6 were analyzed in terms of the selection rules for optical transitions in the corresponding symmetry groups.
The vapor-phase spectra correspond to conformers with the symmetry groupsC
2v
andC
2 for complexes 2–4, with the symmetry groupsD
3h
andD
3 for compound 5, and with the symmetry groupD
2d
for complex 6.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 897–903, May, 1998. 相似文献
7.
T. V. Bezrodnaya V. I. Mel’nik G. A. Puchkovskaya L. I. Savranskii 《Journal of Structural Chemistry》2006,47(1):194-199
An ab initio method has been used to perform quantum mechanical calculations of the formation energy of different conformers of benzophenone: planar molecule, twisted molecule, planar molecule dimer, twisted molecule dimer; electronic and vibrational spectra of these conformers were also obtained. An assessment of the medium (solvent) influence on the optimal geometry, dipole moment and stability of different forms of benzophenone was performed in the self-consistent reaction field approximation. It is shown that the twisted conformer is more stable than the planar one (the difference of free energies is 32 kJ/mol for free molecules) and it becomes even more stable with the increase in solvent polarity. The calculated electronic and vibrational spectra agree well with the experimental data and properly reflect the complication of the vibrational spectrum when passing from the gaseous phase to the condensed state of benzophenone. The difference between spectral properties of the two dimer forms allows their identification from the spectra and qualitative explanation of the observed peculiarities of phosphorescence of the amorphous phase of benzophenone by the stabilization of different conformers. 相似文献
8.
A. A. Ishchenko N. A. Derevyanko S. V. Popov Yu. L. Slominskii V. L. Koval' S. A. Shapovalov N. O. Mchedlov-Petrosyan 《Russian Chemical Bulletin》1997,46(5):910-915
A strong interaction between chromophores of cationic and anionic components was found based on the analysis of electronic
absorption spectra of aqueous solutions of mixtures of cationic indopolycarbocyanines with anionic cyanines. Strong dissimilar
1∶1 associates are formed. Association constants were estimated spectrophotometrically. The main factors determining the degree
of interaction of chromophores were revealed.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 950–955, May, 1997. 相似文献
9.
The polarized electronic absorption spectra of a blue vanadium-doped zircon single crystal, grown by the flux method, has been studied by quantum chemical (CI) calculations in order to determine the position of the V4+ dopant in the zircon host structure. Particularly, the excitation energies and polarizations of V4+ occupying alternate positions, either the zirconium or silicon position or the interstitial site 16g, have been considered. It is concluded that the observed electronic absorption spectra and the color of zirconblue can only be explained if the V4+ chromophore is placed on the respective interstitial position. 相似文献
10.
Summary The electronic spectra forcis-1,3-butadiene andcis-1,3,5-hexatriene have been studied using multiconfiguration second-order perturbation theory (CASPT2) and extended ANO basis sets. The calculations comprise all singlet valence excited states below 8.0 eV, the first 3s, 3p, 3d Rydberg states, and the second 3s state. The four lowest triplet states were also studied. The resulting excitation energies forcis-hexatriene have been used in an assignment of the experimental spectrum, leading to a maximum deviation of 0.13 eV for the vertical transition energies. The calculations place the 11
B
2 state 0.04 eV below the 21
A
1 state. 16 excited states were studied incis-butadiene, using a CASPT2 optimized ground state geometry. The 11
B
2 state was located at 5.58 eV, 0.46 eV below the 21
A
1 state and 0.09 eV above the experimental value. No experimental assignments are available for the 15 other transitions.
On leave from: Departmento de Quimica Física, Universidad de Valencia, Dr. Moliner 50, Burjassot, E-46100-Valencia, Spain 相似文献
11.
Monte-Carlo simulation of liquidN,N-dimethylformamide was performed. The influence or electrostatic and van der Waals interactions on regularities of the mutual
molecular arrangement was investigated. The spatial structure of liquid DMF is determined by the type of molecular packing
and steric factors and is close to a random closely packed system of soft spheres. The electrostatic interactions only affect
the mutual orientation of the molecular
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 21–27, January, 1998. 相似文献
12.
On the basis of optimized structures of two kinds thiophene oligomers, we investigated the configuration and conformation dependent optical and electronic properties of α or β substituted oligothiophene (PT) and oligo(thienylenevinylene) (PTV) isomers, respectively, at the TD‐DFT/6‐31+G(d,p)//PBE0/6‐31G(d) level. The corresponding properties of polymers were predicted by extrapolation method. The broad absorption regions for polythiophene and/or poly(thienylenevinylene) can be ascribed to the coexistence of various conformational and/or configurational isomers with similar energies and each corresponding excited state possessing different absorption spectrum and overlapping each other. Furthermore, the reorganization energies for electron (λe) and hole (λh) of α or β substituted PTV and PT indicate them to be potential ambipolar charge transport materials under the proper operating conditions. Therefore, these results are important because they can provide a rational way for the design of multifunctional materials with broad absorption and ambipolar charge transport properties for solar cells devices. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011 相似文献
13.
Yuexing Zhang Dongdong Qi Xue Cai Jianzhuang Jiang 《International journal of quantum chemistry》2010,110(8):1559-1564
The nature of the near‐IR band in the electronic absorption spectra of bis(tetrapyrrole) rare earth(III) complexes Y(Pc)2 (1), La(Pc)2 (2), Y(Pc)(Por) (3), Y(Pc)[Pc(α‐OCH3)4] (4), Y(Pc)[Pc(α‐OCH3)8] (5), and Y(Pc)[Pc(β‐OCH3)8] (6) was studied on the basis of time‐dependent density functional theory (TD‐DFT) calculations. The electronic dipole moment along the z‐axis in the electronic transition of the near‐IR band in all the studied neutral bis(tetrapyrrole) yttrium(III) and lanthanum(III) double‐deckers is well explained on the basis of the composition analysis of the orbitals involved. The electronic transition in the near‐IR band causes the reversion of the orbital orientation of one tetrapyrrole ring in both homoleptic and heteroleptic bis(tetrapyrrole) rare earth complexes and induces electron transfer from the tetrapyrrole ring with lower orbital energy to the other ring in the heteroleptic bis(tetrapyrrole) rare earth(III) complexes. The near‐IR band can work as an ideal characteristic absorption band to reflect the π–π interaction between the two tetrapyrrole rings in bis(tetrapyrrole) rare earth(III) double‐decker complexes because of its peculiar electronic transition nature. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 相似文献
14.
A procedure that allows for solvation effects is suggested; it is designed for quantum chemical calculations of the electronic spectra of complex compounds. Based on Monte Carlo (MC) simulation of the solvation shell one can calculate the electrostatic potential created by the solvation shell at the sites of all atoms of the complex; appropriate corrections are added to the diagonal elements of the Fock matrix and to the matrix elements of the Hamiltonian in the configuration interaction method. The method suggested has been implemented based on the semiempirical (CINDO) version of the CI (configuration interaction) technique and tested on the following compounds: [Ru(NH3)5(py)]2+, [Ru(NH3)5(pyz)]2+, [Ru(bpy)(CN)4]2?, [Ru(NO)(py)4-NC-Ru(py)4(CN)]3+. 相似文献
15.
D. Loos A. Perjéssy J. B. F. N. Engberts 《Monatshefte für Chemie / Chemical Monthly》1994,125(3):293-299
Summary The infrared spectra of N-cyclohexyl-2-pyrrolidone (NCP) in binary mixtures of hexane and CDCl3 were interpreted theoretically in the region of C=O stretching vibrations using the AM1 semiempirical method. The results were compared with those obtained for N,N-dimethylacetamide (DMA), cyclohexanone (CX) and propanone (PR). Good correlations were found between the carbonyl stretching frequencies and the theoretical parameters of free and solvated species in equilibria with hexane-CDCl3 solvent mixtures.
Theoretische Interpretation von Infrarot-Spektren von N-Cyclohexyl-2-pyrrolidon in Mischungen von Hexan und CDCl3
Zusammenfassung Es wurden die Infrarot-Spektren von N-Cyclohexyl-2-pyrrolidon (NCP) in binären Mischungen von Hexan und CDCl3 im Bereich der C=O Streckschwingung unter Benutzung der semiempirischen AM1-Methode interpretiert. Die Ergebnisse wurden mit denen für N,N-Dimethylacetamid (DMA), Cyclohexanon (CX) und Propanon (PR) verglichen. Es wurde eine gute Korrelation zwischen den Frequenzen der Carbonyl-Streckschwingung und den theoretischen Parametern der freien und solvatisierten Spezies im Gleichgewicht mit den Hexan-CDCl3 Lösungsmittelgemischen gefunden.相似文献
16.
The optical absorption spectrum of cobalt chloride thiourea has been studied at room and liquid air temperatures. The results have been interpreted using group theoretical methods taking into account all the quartet states and several doublet states. Crystal field, electrostatic, and spin-orbit coupling interactions were included to yield the allowed transitions with the relative transition probabilities. The experimental results were interpreted for the following set of parameters: B = 750cm–1, C = 3100cm–1, = 7370cm–1, = -200 cm–1, = 500cm–1, and = 450 cm–1. 相似文献
17.
ESR spectra of liquid and frozen benzene solutions of isotope-enriched95,97,98MoVO(dtc)3 complexes ([
x
Mo]>95%, dtc is theN,N-diethyl dithiocarbamate ligand) and their solid solutions in a matrix of tetraethylthiuram disulfide were studied in the
X-range. Comparison of the experimental and calculated parameters of the ESR spectra shows that the axial symmetry of the
magnetic tensors does not contradict the low symmetry of the complex, in which the “ylic” oxygen and five of six S atoms in
three dithiocarbamate ligands form the coordination sphere of the metal.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2096–2099, November, 1999. 相似文献
18.
J. A. Gonzlez-Orozco 《Journal of Polymer Science.Polymer Physics》1993,31(1):47-59
The influence of thermal history on the dynamic mechanical behavior in the alpha relaxation region of high-density polyethylene (HDPE) is predicted using computer modeling. The model considers the mechanical alpha relaxation as a succession of cooperative single movements occurring within the defect region of the crystal lattice that finally produce a relative displacement between lamellae. A distribution function of the number of such single steps is postulated considering topological properties of the sample: branch content and molecular weight. To carry out the simulation, the model uses the spectrum of the sample subjected to fast cooling as a reference system. In addition, the crystallinity and the segregated material content for the particular thermal history of the object of study are also required. Loss modulus spectra are generated using balance of energy considerations, and a few examples are presented together with several experimental results. © 1993 John Wiley & Sons, Inc. 相似文献
19.
Torres José L. Grethlein Hans E. Lynd Lee R. 《Applied biochemistry and biotechnology》1989,(1):621-633
High energy costs are associated with the recovery of ethanol from fermentation broths. This paper discusses a computer simulation
of the Dartmouth Process, which aims to reduce these costs by the use of IHOSR distillation, extensive heat integration, and
extractive distillation using a salt.
To resolve the uncertainty in modeling alcohol-water-salt vapor-liquid equilibrium, a new and more accurate activity coefficient
model was used. An Aspen™ model was used to generate capital and energy costs for a range of ethanol concentrations in the
feed. Simulation results show that the Dartmouth Process offers substantial economic advantages over benzene azeotropic distillation,
particularly at low feed concentrations. 相似文献
20.
V. E. Pushkarev M. O. Breusova E. V. Shulishov Yu. V. Tomilov 《Russian Chemical Bulletin》2005,54(9):2087-2093
Methods for the selective synthesis of mono-(RPcLnOAc), di-(RPc2Ln), and triphthalocyanines (RPc3Ln2) of rare-earth metals (Ln = Lu, Er, Eu) from symmetrically substituted 2,3,9,10,16,17,23,24-octaalkylphthalocyanines RPcH2 (R = Et, Bu) were developed. The synthesized complexes were characterized by NMR spectroscopy, mass spectrometry, and electronic
absorption spectra. The conditions for 1H NMR spectra recording were optimized. Regularities in changing the spectral properties of the synthesized compounds, depending
on the lanthanide nature and the planarity of metal phthalocyanine complexes, were found.
tom@org.chem.msu.su
Dedicated to Academician A. L. Buchachenko on the occasion of his 70th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2024–2030, September, 2005. 相似文献