Vladimir Pomogaev - Academia.edu (original) (raw)
Papers by Vladimir Pomogaev
Известия высших учебных заведений. Физика, 2021
Theoretical calculations of excited states in complexes of gold and silver three-atom nanocluster... more Theoretical calculations of excited states in complexes of gold and silver three-atom nanoclusters with carbon quantum nanodots have been performed using the M062X functional and the def2SVP {H}/def2TZVP/def2TZVPP{Ag, Au} hybrid basis set. The subsequent calculation of the excited states was performed in the approximation of the time-dependent density functional theory implemented in Gaussian09. The chromophore centers of the points were modeled by heterocyclic molecules of isoquino-diazaanthracene and benzopyrano-naphthydrine. The clusters were attached to the points by means of ethyl mercaptan and a methoxyethane bridge of various lengths. Energy transfer channels are considered depending on the mutual arrangement of energy levels of clusters and heterocycles.
Russian Physics Journal, Mar 24, 2022
Compound 3-benzyl-2H-pyrano[3,2-c]chromene-2,5(6H)-dione(3),wasprepared and fully characterized. ... more Compound 3-benzyl-2H-pyrano[3,2-c]chromene-2,5(6H)-dione(3),wasprepared and fully characterized. The vibrational modes (FT-IR) and NMR data (1 H and 13 C chemical shifts)were compared with the results of Density Functional Theory (DFT) method at theB3LYP/cc-PVTZ level. The calculated vibrational frequenciesand NMR chemical shifts are in good agreement with the experimental results. The electronic (UV-Vis) spectrum was calculated usingthe TD-DFT method in CH 2 Cl 2 with the Polarizable Continuum Model using the integral equation formalism variant (IEFPCM) and was correlated to the experimental spectra. The assignment and analysis of the frontierHOMO and LUMO orbitals indicate that absorption band isoriginated mainly from the π→π* transitions.
Russian Physics Journal, Dec 1, 2020
The article provides a critical analysis of the key spectroscopic data on the study of the struct... more The article provides a critical analysis of the key spectroscopic data on the study of the structure and properties of various molecular solids and phases based on C60 and C70 fullerenes and their derivatives, such as endo-and exohedral complexes with metal ions, hydrogen, helium, and halogens, their electronic and magnetic resonance spectra and, in some cases, the dynamics of the atomic core. Key experimental data have been interpreted based on calculations of the electronic structure of fullerenes and their derivatives.
Известия высших учебных заведений. Физика, 2021
Compound 3-benzyl-2H-pyrano[3,2-c]chromene-2,5(6H)-dione(3),wasprepared and fully characterized. ... more Compound 3-benzyl-2H-pyrano[3,2-c]chromene-2,5(6H)-dione(3),wasprepared and fully characterized. The vibrational modes (FT-IR) and NMR data (1 H and 13 C chemical shifts)were compared with the results of Density Functional Theory (DFT) method at theB3LYP/cc-PVTZ level. The calculated vibrational frequenciesand NMR chemical shifts are in good agreement with the experimental results. The electronic (UV-Vis) spectrum was calculated usingthe TD-DFT method in CH 2 Cl 2 with the Polarizable Continuum Model using the integral equation formalism variant (IEFPCM) and was correlated to the experimental spectra. The assignment and analysis of the frontierHOMO and LUMO orbitals indicate that absorption band isoriginated mainly from the π→π* transitions.
Russian Physics Journal, Feb 1, 2019
The hybrid multilevel approach based on molecular dynamics, quantum mechanics, and statistical th... more The hybrid multilevel approach based on molecular dynamics, quantum mechanics, and statistical theory has been applied to profiles of electronic absorption bands of a number of thiazine dyes (phenothiazine, methylene blue, and methylene green), whose photochemical and biological properties depend on the external medium. The effect of single fragments of the methylene green (MG) molecule on its spectral-luminescent properties is studied. The most preferred geometry for the MG molecule is identified, and its relations with the spectral properties and the solvent nature are established. The energies of the electron states are calculated, and their nature is revealed. The electrostatic potential is analyzed, and the places of the most probable interaction of the molecule with the medium are found. Conclusions on the mechanism of forming the MG absorption spectrum are made based on the observations and calculations performed within the framework of the present work. It is established that the formation of the N–H bonds leads to the formation of an inactive lower excited singlet state and delocalization of the electron charge upon excitation. The position of the maximum of the long-wavelength absorption band of the MG correlates with the donor number of solvents in the series acetonitrile < water < ethanol < isopropanol < dimethyl sulfoxide. The position of the MG electron transition in the region of 630 nm is determined by the interaction of nitrogen and sulfur atoms of the central ring rather than by the increased number of substituents in the structure of the molecule.
Chemical Physics Letters, Apr 1, 2017
Assessment of dierent ab initio and TDDFT methods was studied for calculation of the excitation e... more Assessment of dierent ab initio and TDDFT methods was studied for calculation of the excitation energies of the complexes of pyrimidine bases with positively charged Ag + 3 clusters. Performance of CIS, CIS(D), CC2, ADC(2), MP2, and TDDFT techniques with the use of dierent hybridGGA and metahybridGGA functionals and basis sets is studied. We found that M062X functional shows good accuracy in comparison with the ADC(2) ab initio method and that the geometry optimization approach can strongly aect the excitation spectra of the complexes. Our results may have important implications for further studies of ligandstabilized silver nanoclusters.
Journal of Molecular Liquids, Mar 1, 2019
Photonics of complexes of p-and d-elements with dipyrromethenates is investigated. The role of su... more Photonics of complexes of p-and d-elements with dipyrromethenates is investigated. The role of substituents (their type and localization in the ligand) and of the medium in which dipyrromethenates are placed (solvents, gas mixtures, or solid matrices) is discussed as well as the effect of complexing agents on photonics of the examined complexes. The possibilities for dipyrromethenates application as liquid and solid state laser active media, sensor media for determining the oxygen concentration in a gas mixture, and photosensitizers for singlet oxygen generation in optical devices are presented.
Molecules, Dec 12, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Russian Physics Journal, Mar 1, 2022
Semi-empirical Quantum-Chemical calculations of the photophysical molecular properties of cyanoan... more Semi-empirical Quantum-Chemical calculations of the photophysical molecular properties of cyanoanthracene and surrounding argon cell under different thermodynamical conditions were performed using the MD DL_POLY code. Photophysical scheme of the lowest energy levels and transition probabilities was plotted for the individual molecule. Vibrational profiles of the long-wave absorption electronic band and the first excited Frank-Condon singlet state with fluorescent live-times of the oscillating molecule were obtained. Based on the theoretical results, experimental spectroscopic data have been interpreted.
Theoretical Chemistry Accounts, Jun 3, 2011
Journal of Chemical Theory and Computation, Dec 27, 2022
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Russian Physics Journal, Mar 24, 2022
Известия высших учебных заведений. Физика, 2021
A review of studies on the structures of exotic nano-, meso- and microdiamonds with dodecahedral ... more A review of studies on the structures of exotic nano-, meso- and microdiamonds with dodecahedral and icosahedral symmetry (N/MDPS) is presented. The unique, complex atomic and electronic structure of N/MDPS, due to its high dodecahedral or icosahedral symmetry, leads to promising transport and mechanical properties that are very promising for photonic, quantum and nanomechanical applications. To explain the nature of diamonds, theoretical models were proposed based on the formation of twinned structures consisting of 5 and 20 symmetrically equivalent tetrahedral and prismatic fragments of a face-centered cubic lattice with the formation of star-shaped and icosahedral clusters. It was shown that these twinned nano- and meso-diamonds are limited in size due to the accumulation of uncompensated structural stresses arising from the deviation of angles from the ideal 72º between diamond &amp;lt;111&amp;gt; facets in tetrahedral fragments of a face-centered cubic lattice, up to 70.5º between five symmetrically equivalent twinned fragments.
Russian Physics Journal, Aug 1, 2016
The optical spectra of Cu 2þ in dioptase are calculated using crystal-field theory. Good agreemen... more The optical spectra of Cu 2þ in dioptase are calculated using crystal-field theory. Good agreement between measured and calculated energy values is obtained under D 4h point-symmetry approximation. The electron paramagnetic resonance g factors, g // and g ? , are also investigated from high-order perturbation formulae. The local structure of Cu 2þ in dioptase is obtained using these formulae. Theoretical results are in perfect agreement with experimental findings.
Journal of Physical Chemistry C, May 7, 2020
The electronic structure, transition probabilities and corresponding quantum yields of fluorescen... more The electronic structure, transition probabilities and corresponding quantum yields of fluorescence in a family of dihalogen-tetraphenyl-aza-BODIPY were calculated at the Time-Dependent Density Functional and post-Hartree-Fock levels of theory. Excellent agreement between theoretical and experimental spectral-luminescent data was achieved with the HSE06 functional and the 6-311G* basis set. Since the fluorescence can be quenched through nonradiative intersystem spin crossing transitions from the lowest photoactive singlet state to triplet excited states, spin-orbit coupling matrix elements were calculated and applied along with Marcus-Levich-Jortner theory, leading to satisfactory agreement for the lifetimes in comparison with available experimental data. The anomalous dependence of the fluorescence efficiency on the atomic number of the halogen congeners was elucidated and shown to be due to an inversion between the fluorescent and the nearest triplet states in the iodinated compounds. The high rate of fluorescence quenching by intersystem crossings and the probability of collisions in a solvent between oxygen molecules and the molecules studied, shows that these molecules can provide efficient triplet sensitization. The most preferable sites for such interactions were predicted using electrostatic potential mapping at the extreme positive and negative charge points.
Journal of Physical Chemistry Letters, Oct 7, 2021
The molecular orbital (MO) concept is a useful tool, which relates the molecular ground-state ene... more The molecular orbital (MO) concept is a useful tool, which relates the molecular ground-state energy with the energies (and occupations) of the individual orbitals. However, analysis of the excited states from linear response computations is performed in terms of the initial state MOs or some other forms of orbitals, e.g., natural or natural transition orbitals. Because these orbitals lack the respective energies, they do not allow developing a consistent orbital picture of the excited states. Herein, we argue that Dyson's orbitals enable description of the response states compatible with the concepts of molecular orbital theory. The Dyson orbitals and their energies obtained by mixed-reference spin-flip time-dependent density functional theory (MRSF-TDDFT) for the response ground state are remarkably similar to the canonical MOs obtained by the usual DFT calculation. For excited states, the Dyson orbitals provide a chemically sensible picture of the electronic transitions, thus bridging the chasm between orbital theory and response computations.
Journal of Physical Chemistry C, Feb 3, 2021
Fluorescent beacons based on silver (Ag) clusters for DNA/RNA detection represent a new type of t... more Fluorescent beacons based on silver (Ag) clusters for DNA/RNA detection represent a new type of turn-on probe that fluoresces upon hybridization to target nucleobase sequences. Physical–chemical me...
Journal of Physics and Chemistry of Solids, Nov 1, 2019
The role of strong electron correlations in determination of band structure and charge distributi... more The role of strong electron correlations in determination of band structure and charge distribution of transition metal dihalide monolayers,
Известия высших учебных заведений. Физика, 2021
Theoretical calculations of excited states in complexes of gold and silver three-atom nanocluster... more Theoretical calculations of excited states in complexes of gold and silver three-atom nanoclusters with carbon quantum nanodots have been performed using the M062X functional and the def2SVP {H}/def2TZVP/def2TZVPP{Ag, Au} hybrid basis set. The subsequent calculation of the excited states was performed in the approximation of the time-dependent density functional theory implemented in Gaussian09. The chromophore centers of the points were modeled by heterocyclic molecules of isoquino-diazaanthracene and benzopyrano-naphthydrine. The clusters were attached to the points by means of ethyl mercaptan and a methoxyethane bridge of various lengths. Energy transfer channels are considered depending on the mutual arrangement of energy levels of clusters and heterocycles.
Russian Physics Journal, Mar 24, 2022
Compound 3-benzyl-2H-pyrano[3,2-c]chromene-2,5(6H)-dione(3),wasprepared and fully characterized. ... more Compound 3-benzyl-2H-pyrano[3,2-c]chromene-2,5(6H)-dione(3),wasprepared and fully characterized. The vibrational modes (FT-IR) and NMR data (1 H and 13 C chemical shifts)were compared with the results of Density Functional Theory (DFT) method at theB3LYP/cc-PVTZ level. The calculated vibrational frequenciesand NMR chemical shifts are in good agreement with the experimental results. The electronic (UV-Vis) spectrum was calculated usingthe TD-DFT method in CH 2 Cl 2 with the Polarizable Continuum Model using the integral equation formalism variant (IEFPCM) and was correlated to the experimental spectra. The assignment and analysis of the frontierHOMO and LUMO orbitals indicate that absorption band isoriginated mainly from the π→π* transitions.
Russian Physics Journal, Dec 1, 2020
The article provides a critical analysis of the key spectroscopic data on the study of the struct... more The article provides a critical analysis of the key spectroscopic data on the study of the structure and properties of various molecular solids and phases based on C60 and C70 fullerenes and their derivatives, such as endo-and exohedral complexes with metal ions, hydrogen, helium, and halogens, their electronic and magnetic resonance spectra and, in some cases, the dynamics of the atomic core. Key experimental data have been interpreted based on calculations of the electronic structure of fullerenes and their derivatives.
Известия высших учебных заведений. Физика, 2021
Compound 3-benzyl-2H-pyrano[3,2-c]chromene-2,5(6H)-dione(3),wasprepared and fully characterized. ... more Compound 3-benzyl-2H-pyrano[3,2-c]chromene-2,5(6H)-dione(3),wasprepared and fully characterized. The vibrational modes (FT-IR) and NMR data (1 H and 13 C chemical shifts)were compared with the results of Density Functional Theory (DFT) method at theB3LYP/cc-PVTZ level. The calculated vibrational frequenciesand NMR chemical shifts are in good agreement with the experimental results. The electronic (UV-Vis) spectrum was calculated usingthe TD-DFT method in CH 2 Cl 2 with the Polarizable Continuum Model using the integral equation formalism variant (IEFPCM) and was correlated to the experimental spectra. The assignment and analysis of the frontierHOMO and LUMO orbitals indicate that absorption band isoriginated mainly from the π→π* transitions.
Russian Physics Journal, Feb 1, 2019
The hybrid multilevel approach based on molecular dynamics, quantum mechanics, and statistical th... more The hybrid multilevel approach based on molecular dynamics, quantum mechanics, and statistical theory has been applied to profiles of electronic absorption bands of a number of thiazine dyes (phenothiazine, methylene blue, and methylene green), whose photochemical and biological properties depend on the external medium. The effect of single fragments of the methylene green (MG) molecule on its spectral-luminescent properties is studied. The most preferred geometry for the MG molecule is identified, and its relations with the spectral properties and the solvent nature are established. The energies of the electron states are calculated, and their nature is revealed. The electrostatic potential is analyzed, and the places of the most probable interaction of the molecule with the medium are found. Conclusions on the mechanism of forming the MG absorption spectrum are made based on the observations and calculations performed within the framework of the present work. It is established that the formation of the N–H bonds leads to the formation of an inactive lower excited singlet state and delocalization of the electron charge upon excitation. The position of the maximum of the long-wavelength absorption band of the MG correlates with the donor number of solvents in the series acetonitrile < water < ethanol < isopropanol < dimethyl sulfoxide. The position of the MG electron transition in the region of 630 nm is determined by the interaction of nitrogen and sulfur atoms of the central ring rather than by the increased number of substituents in the structure of the molecule.
Chemical Physics Letters, Apr 1, 2017
Assessment of dierent ab initio and TDDFT methods was studied for calculation of the excitation e... more Assessment of dierent ab initio and TDDFT methods was studied for calculation of the excitation energies of the complexes of pyrimidine bases with positively charged Ag + 3 clusters. Performance of CIS, CIS(D), CC2, ADC(2), MP2, and TDDFT techniques with the use of dierent hybridGGA and metahybridGGA functionals and basis sets is studied. We found that M062X functional shows good accuracy in comparison with the ADC(2) ab initio method and that the geometry optimization approach can strongly aect the excitation spectra of the complexes. Our results may have important implications for further studies of ligandstabilized silver nanoclusters.
Journal of Molecular Liquids, Mar 1, 2019
Photonics of complexes of p-and d-elements with dipyrromethenates is investigated. The role of su... more Photonics of complexes of p-and d-elements with dipyrromethenates is investigated. The role of substituents (their type and localization in the ligand) and of the medium in which dipyrromethenates are placed (solvents, gas mixtures, or solid matrices) is discussed as well as the effect of complexing agents on photonics of the examined complexes. The possibilities for dipyrromethenates application as liquid and solid state laser active media, sensor media for determining the oxygen concentration in a gas mixture, and photosensitizers for singlet oxygen generation in optical devices are presented.
Molecules, Dec 12, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Russian Physics Journal, Mar 1, 2022
Semi-empirical Quantum-Chemical calculations of the photophysical molecular properties of cyanoan... more Semi-empirical Quantum-Chemical calculations of the photophysical molecular properties of cyanoanthracene and surrounding argon cell under different thermodynamical conditions were performed using the MD DL_POLY code. Photophysical scheme of the lowest energy levels and transition probabilities was plotted for the individual molecule. Vibrational profiles of the long-wave absorption electronic band and the first excited Frank-Condon singlet state with fluorescent live-times of the oscillating molecule were obtained. Based on the theoretical results, experimental spectroscopic data have been interpreted.
Theoretical Chemistry Accounts, Jun 3, 2011
Journal of Chemical Theory and Computation, Dec 27, 2022
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Russian Physics Journal, Mar 24, 2022
Известия высших учебных заведений. Физика, 2021
A review of studies on the structures of exotic nano-, meso- and microdiamonds with dodecahedral ... more A review of studies on the structures of exotic nano-, meso- and microdiamonds with dodecahedral and icosahedral symmetry (N/MDPS) is presented. The unique, complex atomic and electronic structure of N/MDPS, due to its high dodecahedral or icosahedral symmetry, leads to promising transport and mechanical properties that are very promising for photonic, quantum and nanomechanical applications. To explain the nature of diamonds, theoretical models were proposed based on the formation of twinned structures consisting of 5 and 20 symmetrically equivalent tetrahedral and prismatic fragments of a face-centered cubic lattice with the formation of star-shaped and icosahedral clusters. It was shown that these twinned nano- and meso-diamonds are limited in size due to the accumulation of uncompensated structural stresses arising from the deviation of angles from the ideal 72º between diamond &amp;lt;111&amp;gt; facets in tetrahedral fragments of a face-centered cubic lattice, up to 70.5º between five symmetrically equivalent twinned fragments.
Russian Physics Journal, Aug 1, 2016
The optical spectra of Cu 2þ in dioptase are calculated using crystal-field theory. Good agreemen... more The optical spectra of Cu 2þ in dioptase are calculated using crystal-field theory. Good agreement between measured and calculated energy values is obtained under D 4h point-symmetry approximation. The electron paramagnetic resonance g factors, g // and g ? , are also investigated from high-order perturbation formulae. The local structure of Cu 2þ in dioptase is obtained using these formulae. Theoretical results are in perfect agreement with experimental findings.
Journal of Physical Chemistry C, May 7, 2020
The electronic structure, transition probabilities and corresponding quantum yields of fluorescen... more The electronic structure, transition probabilities and corresponding quantum yields of fluorescence in a family of dihalogen-tetraphenyl-aza-BODIPY were calculated at the Time-Dependent Density Functional and post-Hartree-Fock levels of theory. Excellent agreement between theoretical and experimental spectral-luminescent data was achieved with the HSE06 functional and the 6-311G* basis set. Since the fluorescence can be quenched through nonradiative intersystem spin crossing transitions from the lowest photoactive singlet state to triplet excited states, spin-orbit coupling matrix elements were calculated and applied along with Marcus-Levich-Jortner theory, leading to satisfactory agreement for the lifetimes in comparison with available experimental data. The anomalous dependence of the fluorescence efficiency on the atomic number of the halogen congeners was elucidated and shown to be due to an inversion between the fluorescent and the nearest triplet states in the iodinated compounds. The high rate of fluorescence quenching by intersystem crossings and the probability of collisions in a solvent between oxygen molecules and the molecules studied, shows that these molecules can provide efficient triplet sensitization. The most preferable sites for such interactions were predicted using electrostatic potential mapping at the extreme positive and negative charge points.
Journal of Physical Chemistry Letters, Oct 7, 2021
The molecular orbital (MO) concept is a useful tool, which relates the molecular ground-state ene... more The molecular orbital (MO) concept is a useful tool, which relates the molecular ground-state energy with the energies (and occupations) of the individual orbitals. However, analysis of the excited states from linear response computations is performed in terms of the initial state MOs or some other forms of orbitals, e.g., natural or natural transition orbitals. Because these orbitals lack the respective energies, they do not allow developing a consistent orbital picture of the excited states. Herein, we argue that Dyson's orbitals enable description of the response states compatible with the concepts of molecular orbital theory. The Dyson orbitals and their energies obtained by mixed-reference spin-flip time-dependent density functional theory (MRSF-TDDFT) for the response ground state are remarkably similar to the canonical MOs obtained by the usual DFT calculation. For excited states, the Dyson orbitals provide a chemically sensible picture of the electronic transitions, thus bridging the chasm between orbital theory and response computations.
Journal of Physical Chemistry C, Feb 3, 2021
Fluorescent beacons based on silver (Ag) clusters for DNA/RNA detection represent a new type of t... more Fluorescent beacons based on silver (Ag) clusters for DNA/RNA detection represent a new type of turn-on probe that fluoresces upon hybridization to target nucleobase sequences. Physical–chemical me...
Journal of Physics and Chemistry of Solids, Nov 1, 2019
The role of strong electron correlations in determination of band structure and charge distributi... more The role of strong electron correlations in determination of band structure and charge distribution of transition metal dihalide monolayers,