Resonance dynamical intermolecular interaction in the crystals of pure and binary mixture n-paraffins

G. O. Puchkovska, V. D. Danchuk, S. P. Makarenko, A. P. Kravchuk, E. N. Kotelnikova, S. K. Filatov

Результат исследований: Научные публикации в периодических изданияхстатьянаучнаярецензирование

6 Цитирования (Scopus)

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In the present paper, we report temperature dependent FTIR spectra studies of Davydov splitting value for CH2 rocking vibrations of pure crystalline n-paraffins CnH2n+2 (n is the number of carbon atoms) and some isomorphically substituted binary mixtures of n-paraffins C22H46:C24H50. Temperature dependencies of Davydov splitting value have been shown to be characterized by the amount of irregularities (sharp decreasing), which corresponds to the phase transitions into the high-temperature (hexagonal) state for pure n-paraffins or different rotator crystalline states for the mixtures. Statistic and dynamic models have been proposed, which provides an adequate description of the observed effect. In the framework of these models, two different mechanisms are responsible for the temperature behavior of the vibrational mode splitting value. Besides the thermal expansion of crystals at heating, the quenching of vibrational excitons on the orientational defects of different nature takes place, accompanied with the breakage of the crystal lattice translational symmetry. The creation of such defects is resulted from the excitation of librational and rotational molecular degrees of freedom at the crystal polymorphic transitions into different rotary crystalline states. The manifestation of the resonance dynamical intermolecular interaction in the spectra of intramolecular vibrations in these crystals has been theoretically analyzed in terms of stochastic equations, taking into consideration the above mentioned phase transition. We have obtained the explicit expression for the theoretically predicted dependence of Davydov splitting value on temperature. The absorption bands, corresponding to Davydov splitting components, have been shown to approach rapidly each other at the transition to the high-temperature (hexagonal) phase. Computer simulation of such dependence has been performed for some aliphatic compounds. Good agreement between the experimental and computer simulation results has been obtained. The theoretical approach developed in the present paper for the resonance dynamical intermolecular interaction near such transitions from the three-dimensional to one-dimensional phase of crystalline n-paraffins has a general character and can be applied to the description of some specific features observed in the vibrational spectra of rotary crystals.

Язык оригиналаанглийский
Страницы (с-по)39-45
Число страниц7
ЖурналJournal of Molecular Structure
Том708
Номер выпуска1-3
DOI
СостояниеОпубликовано - 1 дек 2004

Ключевые слова

    Предметные области Scopus

    • Аналитическая химия
    • Спектроскопия
    • Органическая химия
    • Неорганическая химия

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    title = "Resonance dynamical intermolecular interaction in the crystals of pure and binary mixture n-paraffins",
    abstract = "In the present paper, we report temperature dependent FTIR spectra studies of Davydov splitting value for CH2 rocking vibrations of pure crystalline n-paraffins CnH2n+2 (n is the number of carbon atoms) and some isomorphically substituted binary mixtures of n-paraffins C22H46:C24H50. Temperature dependencies of Davydov splitting value have been shown to be characterized by the amount of irregularities (sharp decreasing), which corresponds to the phase transitions into the high-temperature (hexagonal) state for pure n-paraffins or different rotator crystalline states for the mixtures. Statistic and dynamic models have been proposed, which provides an adequate description of the observed effect. In the framework of these models, two different mechanisms are responsible for the temperature behavior of the vibrational mode splitting value. Besides the thermal expansion of crystals at heating, the quenching of vibrational excitons on the orientational defects of different nature takes place, accompanied with the breakage of the crystal lattice translational symmetry. The creation of such defects is resulted from the excitation of librational and rotational molecular degrees of freedom at the crystal polymorphic transitions into different rotary crystalline states. The manifestation of the resonance dynamical intermolecular interaction in the spectra of intramolecular vibrations in these crystals has been theoretically analyzed in terms of stochastic equations, taking into consideration the above mentioned phase transition. We have obtained the explicit expression for the theoretically predicted dependence of Davydov splitting value on temperature. The absorption bands, corresponding to Davydov splitting components, have been shown to approach rapidly each other at the transition to the high-temperature (hexagonal) phase. Computer simulation of such dependence has been performed for some aliphatic compounds. Good agreement between the experimental and computer simulation results has been obtained. The theoretical approach developed in the present paper for the resonance dynamical intermolecular interaction near such transitions from the three-dimensional to one-dimensional phase of crystalline n-paraffins has a general character and can be applied to the description of some specific features observed in the vibrational spectra of rotary crystals.",
    keywords = "Davydov splitting, FTIR spectra, n-Paraffin, Rotary crystal state",
    author = "Puchkovska, {G. O.} and Danchuk, {V. D.} and Makarenko, {S. P.} and Kravchuk, {A. P.} and Kotelnikova, {E. N.} and Filatov, {S. K.}",
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    Resonance dynamical intermolecular interaction in the crystals of pure and binary mixture n-paraffins. / Puchkovska, G. O.; Danchuk, V. D.; Makarenko, S. P.; Kravchuk, A. P.; Kotelnikova, E. N.; Filatov, S. K.

    В: Journal of Molecular Structure, Том 708, № 1-3, 01.12.2004, стр. 39-45.

    Результат исследований: Научные публикации в периодических изданияхстатьянаучнаярецензирование

    TY - JOUR

    T1 - Resonance dynamical intermolecular interaction in the crystals of pure and binary mixture n-paraffins

    AU - Puchkovska, G. O.

    AU - Danchuk, V. D.

    AU - Makarenko, S. P.

    AU - Kravchuk, A. P.

    AU - Kotelnikova, E. N.

    AU - Filatov, S. K.

    PY - 2004/12/1

    Y1 - 2004/12/1

    N2 - In the present paper, we report temperature dependent FTIR spectra studies of Davydov splitting value for CH2 rocking vibrations of pure crystalline n-paraffins CnH2n+2 (n is the number of carbon atoms) and some isomorphically substituted binary mixtures of n-paraffins C22H46:C24H50. Temperature dependencies of Davydov splitting value have been shown to be characterized by the amount of irregularities (sharp decreasing), which corresponds to the phase transitions into the high-temperature (hexagonal) state for pure n-paraffins or different rotator crystalline states for the mixtures. Statistic and dynamic models have been proposed, which provides an adequate description of the observed effect. In the framework of these models, two different mechanisms are responsible for the temperature behavior of the vibrational mode splitting value. Besides the thermal expansion of crystals at heating, the quenching of vibrational excitons on the orientational defects of different nature takes place, accompanied with the breakage of the crystal lattice translational symmetry. The creation of such defects is resulted from the excitation of librational and rotational molecular degrees of freedom at the crystal polymorphic transitions into different rotary crystalline states. The manifestation of the resonance dynamical intermolecular interaction in the spectra of intramolecular vibrations in these crystals has been theoretically analyzed in terms of stochastic equations, taking into consideration the above mentioned phase transition. We have obtained the explicit expression for the theoretically predicted dependence of Davydov splitting value on temperature. The absorption bands, corresponding to Davydov splitting components, have been shown to approach rapidly each other at the transition to the high-temperature (hexagonal) phase. Computer simulation of such dependence has been performed for some aliphatic compounds. Good agreement between the experimental and computer simulation results has been obtained. The theoretical approach developed in the present paper for the resonance dynamical intermolecular interaction near such transitions from the three-dimensional to one-dimensional phase of crystalline n-paraffins has a general character and can be applied to the description of some specific features observed in the vibrational spectra of rotary crystals.

    AB - In the present paper, we report temperature dependent FTIR spectra studies of Davydov splitting value for CH2 rocking vibrations of pure crystalline n-paraffins CnH2n+2 (n is the number of carbon atoms) and some isomorphically substituted binary mixtures of n-paraffins C22H46:C24H50. Temperature dependencies of Davydov splitting value have been shown to be characterized by the amount of irregularities (sharp decreasing), which corresponds to the phase transitions into the high-temperature (hexagonal) state for pure n-paraffins or different rotator crystalline states for the mixtures. Statistic and dynamic models have been proposed, which provides an adequate description of the observed effect. In the framework of these models, two different mechanisms are responsible for the temperature behavior of the vibrational mode splitting value. Besides the thermal expansion of crystals at heating, the quenching of vibrational excitons on the orientational defects of different nature takes place, accompanied with the breakage of the crystal lattice translational symmetry. The creation of such defects is resulted from the excitation of librational and rotational molecular degrees of freedom at the crystal polymorphic transitions into different rotary crystalline states. The manifestation of the resonance dynamical intermolecular interaction in the spectra of intramolecular vibrations in these crystals has been theoretically analyzed in terms of stochastic equations, taking into consideration the above mentioned phase transition. We have obtained the explicit expression for the theoretically predicted dependence of Davydov splitting value on temperature. The absorption bands, corresponding to Davydov splitting components, have been shown to approach rapidly each other at the transition to the high-temperature (hexagonal) phase. Computer simulation of such dependence has been performed for some aliphatic compounds. Good agreement between the experimental and computer simulation results has been obtained. The theoretical approach developed in the present paper for the resonance dynamical intermolecular interaction near such transitions from the three-dimensional to one-dimensional phase of crystalline n-paraffins has a general character and can be applied to the description of some specific features observed in the vibrational spectra of rotary crystals.

    KW - Davydov splitting

    KW - FTIR spectra

    KW - n-Paraffin

    KW - Rotary crystal state

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    U2 - 10.1016/j.molstruc.2004.02.010

    DO - 10.1016/j.molstruc.2004.02.010

    M3 - Article

    VL - 708

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    EP - 45

    JO - Journal of Molecular Structure

    JF - Journal of Molecular Structure

    SN - 0022-2860

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