137 research outputs found
VIBRATIONAL ANHARMONICITY AND SCALING THE QUANTUM MECHANICAL MOLECULAR FORCE FIELD
No full text Yu. N. Panchenko, P. Pulay and F. T\""{o}r\""{o}k, J. Mol. Struct. 34, 283 (1976); V.I. Pupyshev, Yu.N. Panchenko, Ch. W. Bock and G. Pongor, J. Chem. Phys. 94, 1247 (1991); Yu. N. Panchenko, G.R. De Mar\'{e} and V.I. Pupyshev, J. Phys. Chem. 99, 17544 (1995); Yu. N. Panchenko, Moscow Univ. Chem. Bull. 51 (5), 23 (1996). D.M. Dennison, Rev. Mod, Phys. 12, 175 (1940); G.E. Hansen and D.M. Dennison, J. Chem. Phys. 20, 313 (1952).Author Institution: Laboratory of Molecular Spectroscopy, Division of Physical Chemistry, Department of Chemistry, M.V. Lomonosov Moscow State University; Laboratory of Molecular Structure and Quantum Mechanics, Division of Physical Chemistry, Department of Chemistry, M.V. Lomonosov Moscow State University; Chemistry Department, Philadelphia College of Textiles \& ScienceThe interrelationship between the scale factors obtained using Pulay's from the anharmonic and the harmonized vibrational frequencies of a light molecule and its heavy analogue is considered in terms of a Morse potential. The determination of the scale factors from the vibrational frequencies of a light molecule is shown to result in smaller deviations of the calculated and experimental vibrational frequencies of its heavy analogue than those of the reverse procedure. In this context the extent to which Dennison's is satisfied is also discussed
TRANSFERABILITY OF PULAY'S SCALE FACTORS IN THE IVa GROUP OF THE MENDELEYEV PERIODIC SYSTEM
No full text P.C. Hariharan and J.A. Pople, Chem. Phys. Lett. 16, 217 (1972). Yu. N. Pancbenko, P. Pulay and F. T\""{o}r\""{o}k, J. Mol. Structure 34, 283 (1976); V.I. Pupyshev, Yu. N. Panchenko, Ch. W. Bock and G. Pongor, J. Chem. Phys. 94, 1247 (1991); Yu. N. Panchenko, G.R. De Mar\'{e} and V.I. Pupyshev, J. Phys. Chem. 99, 17544 (1995); Yu. N. Panchenko, Moscow Univ. Chem. Bull. 51 (5), 23 (1996).Author Institution: Laboratory of Molecular Spectroscopy, Division of Physical Chemistry, Department of Chemistry, M.V. Lomonosov Moscow State University; Laboratoire de Chimie Physique Mol\'{e}culaire, Facult\'{e} des Sciences, CP 160/09, Universit\'{e} Libre de Bruxelles; Laboratory of Molecular Structure and Quantum Mechanics, Division of Physical Chemistry, Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119899, Russian Federation.Ab initio quantum mechanical calculations were performed for structures and force fields of 3,3-dimethylbutene-1, cyclopropene, 1-methylcyclopropene, and 1-trimethylsilyl-, 1,2-bis(trimethylsilyl)-, 1-trimethylgermyl-, 1,2-bis(trimethylgermyl)-, 1-trimethylstannyl-, and 1,2-bis(trimethylstannyl)-3,3-dimethylcyclopropene. Scale factors for correction of the quantum mechanical force fields of cyclopropene, 1-methylcyclopropene, and 3,3-dimethylbutene-1 were determined using Pulay's scaling Only the experimental vibrational frequencies of the light isotopomers of these molecules were used in the scaling procedure. The set of scale factors obtained was transferred to the quantum mechanical force fields of all the other molecules mentioned above. The vibrational problems for these molecules were solved. Complete vibrational analyses were carried out for the whole set of these related compounds. Transferability of scale factors for series of related compounds of cyclopropene with heteroatoms from the IVa group of the Mendeleyev Periodic System of chemical elements was demonstrated
METHODS OF SCALING QUANTUM MECHANICAL MOLECULAR FORCE FIELDS
No full textA.G. Yagola, I.V. Kochikov, G.M. Kuramshina and Yu. A. Pentin. ``Inverse Problems of Vibrational Spectroscopy"". VSP, Utrecht. The Netherlands, 1999, Chapter 11, p. 259. Yu, N. Panchenko, J. Mol. Street. 410-411. 327 (1997).Author Institution: Laboratory of Molecular Spectroscopy, Division of Physical Chemistry, Department of Chemistry, M.V. Lomonosov Moscow State UniversityA comparative analysis of various methods of empirical scaling of the quantum mechanical harmonic molecular force fields has been performed. The Pulay method of scaling is stressed to be applicable most successfully in the case where the quantum mechanical force field is determined close to the Hartree-Fock limit. This makes it possible to carry out correction of this force field with maximal retention of the peculiarities inherent in the the molecule under investigation. The solution of the inverse vibrational problem using quantum mechanical force field as a starting one may be considered to be the limiting case of scaling with maximum number of scale factors. Such approach corresponds to the traditional philosophy that searching force field should be closest to the starting . On the contrary, the main physical criterion used in the Pulay scaling procedure is closeness of the vibrational modes determined from the scaled force field to the vibrational modes obtained from the starting quantum mechanical force
TRANSFERABILITY OF SCALE FACTORS VERSUS TRANSFERABILITY OF FORCE CONSTANTS
No full textA.G. Yagola, I.V. Kochikov, G.M. Kuramshina and Yu. A. Pentin. ``Inverse Problems of Vibrational Spectroscopy"". VSP, Utrecht, The Netherlands, 1999. Chapter 11, p. 259. Yu, N. Panchenko, J. Struct. Chem. 40, 548 (1999) (Russian pagination).Author Institution: Laboratory of Molecular Spectroscopy, Division of Physical Chemistry, Department of Chemistry, M.V. Lomonosov Moscow State UniversityIn the techniques for solving the inverse vibrational problem on the basis of quantum-mechanical force fields, it is assumed that the force constants are the same for quasi-equivalent coordinates in similar structural moieties of related . Clearly, this approach ignores characteristics of the force field of each particular molecule. Indeed, this concept implies that all responsibility for possible shifts of frequencies and other spectral features of related molecules (to which the force constants are transferred) lies with changes in the inverse kinetic energy matrix. With scaling of quantum-mechanical force fields, the relative errors indroduced during quantum-mechanical calculations of force constants at a certain theoretical level are assumed to be approximately the same for quasi-equivalent coordinates in similar structural fragments of related molecules. This assumption imposes less stringent constraints than the assumption of trasferability of force constants in series of related
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The Generalization of Fatou’s Theorem and Its Converse
No full textWe consider a function K(x) on R n which satisfies certain decay conditions. Let µ be a signed measure on R n . For y > 0 set K[µ](x, y) = Z Rn 1 y n K( x − t y )dµ(t). In this paper we investigate the relationship between the derivative of µ at a point x ∈ R n and the non-tangential limit of K[µ](x, y) (thought of as a function in R n+1 + )
PLP-ESR monitoring of midchain radicals in n-butyl acrylate polymerization
No full textThe percentage of two types of free radicals occurring within n-butyl acrylate pulsed laser polymerization (PLP) has been measured via ESR spectroscopy. Polymerization in solution of toluene, at monomer concentrations between 0.50 and 2.53 mol L-1 and temperatures between -50 and 70 °C, was induced by 351 nm excimer laser pulses applied at a repetition rate of 20 Hz. The ESR spectra obtained at low degrees of monomer conversion may be adequately represented by superimposing a six-component four-line spectrum assigned to secondary propagating radicals (SPRs) and a nine-line spectrum assigned to tertiary midchain radicals produced by backbiting (MCR1s). The percentage contribution to total radical concentration of the latter species, which is produced from an SPR by a 1,5-H shift backbiting reaction, is negligible at -50 °C and is close to 80% at 70 °C. The transition of an SPR to a MCR1 species invalidates the linear correlation of time t after applying a laser pulse with the size of the growing radical. The observed high concentration of MCR1 species explains the known severe limitations met in acrylate PLP-SEC experiments directed toward measuring the propagation rate of acrylate radicals with chain-end functionality
Leader of the Last Testament Church Vissarion arrested
No full textAuthor: Alexander Panchenko On September 22, 2020, Sergey Torop (also known as Vissarion Christ), Vadim Red’kin, and Vladimir Vedernikov, the leaders of the Last Testament Church (the LTC), were arrested in the Krasnoyarsk region by police officers. The LTC, also known as the “Vissarion movement” (see Joseph Kellner’s post on this blog), was founded in 1991 by an amateur artist Sergei Torop (b. 1961), who claims to be a new incarnation of Jesus Christ and who has now come to the people und..
Роль освіти у формуванні соціокультурної компетентності у дітей молодшого шкільного віку
No full textThe author explores the problem of developing sociocultural competence in primary school pupils. According to the author, sociocultural competence is the basis for developing interpersonal communication skills, empathy, and a sense of belonging to a multicultural world in primary school children.
Автор досліджує проблему формування соціокультурної компетентності у молодших школярів. Для дітей молодшого шкільного віку, на думку автора, соціокультурна компетентність є основою для розвитку їхніх навичок міжособистісного спілкування, емпатії та почуття причетності до мультикультурного світу
CRIME COUNTERACTION AS STRUGGLE FOR HUMAN RIGHTS
No full textThe article views the issues of solving the human rights problem by means of crime counteraction. The author suggests ways of increasing the criminal policy efficiency by broader inclusion of the state and public control elements into its structure
The Problems of Policy and Strategy of National Security of Russia in Transcaucasia
No full textThe author characterizes the geopolitical situation in Transcaucasia at the beginning of ХХI century which is defined by the processes that occur in each of the Transcaucasian states (Azerbaijan, Armenia, Georgia), in relations between them and between each of these states and Russia. The peculiarities of interaction and cooperation of Transcaucasian states with leading world powers are also analyzed by the author
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