Spectral effects of intermolecular interaction and phase transitions in pure n-paraffin crystals

Galyna O. Puchkovska; V. D. Danchuk; A. P. Kravchuk; Jan I. Kukielski

doi:10.1117/12.569835

20 July 2004 Spectral effects of intermolecular interaction and phase transitions in pure n-paraffin crystals

Galyna O. Puchkovska, V. D. Danchuk, A. P. Kravchuk, Jan I. Kukielski

Proceedings Volume 5507, XVI International Conference on Spectroscopy of Molecules and Crystals; (2004) https://doi.org/10.1117/12.569835
Event: XVI International Conference on Spectroscopy of Molecules and Crystals, 2003, Sevastopol, Ukraine

Abstract

In JR spectra for region of phase transition "order-orientation disorder" is observed the temperature dependence of the Davydov splitting value for in-phase CH₂ rocking vibrations of pure crystalline n-paraffins C_nH_2n+2(n=19, 21, 23, 30, 32). Within the frameworks of crystal thermal expansion model the Davydov splitting value of vibration frequencies for pure n-paraffins weakly depends on temperature in all temperature range of crystalline phase existence. A statistic and dynamic model is proposed, which provides adequate description of the observed effect. Jn the framework of this model, the damping of vibrational excitons on orientational defects of different nature takes place. Genesis of such defects is connected with excitation of librational and rotational molecular degrees of freedom at the crystal transitions into high-temperature orthorhombic and hexagonal crystalline states. Theoretical analysis of the effect of resonance dynamical intermolecular interaction on the spectra of intramolecular vibrations of the crystals was performed in terms of stochastic equations with account of phase transitions. Computer simulation of such dependence was performed for pure n-paraffin compounds. Good agreement between the experimental and computer simulation results was obtained.

Citation Download Citation

Galyna O. Puchkovska, V. D. Danchuk, A. P. Kravchuk, and Jan I. Kukielski "Spectral effects of intermolecular interaction and phase transitions in pure n-paraffin crystals", Proc. SPIE 5507, XVI International Conference on Spectroscopy of Molecules and Crystals, (20 July 2004); https://doi.org/10.1117/12.569835

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available