Motion of Molecules at Plateau Region: Case of Propylene Glycol

Abstract:

Positronium annihilation measurements on normal and deuterated propylene glycols have been performed at the temperature range (14-325) K. The so-called “plateau region” in the dependence of the ortho-positronium lifetime on temperature has been observed at temperatures T > 270 K. Free volume differences between normal and deuterated propylene glycols have been observed at ≈ 100 K and ≈ 225 K. Assuming a linear expansion of propylene glycol at T > 260 K, we can estimate the velocity of moving molecules or part of them that surround a free volume. It appears to be 2.5 cm/s (0.25 Å/ns) in average.

• Periodical: Materials Science Forum (Volume 733)
• Pages: 80-83
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.733.80
• Online since: November 2012
• Authors: Viktor Majerník, Jozef Krištiak, Ondrej Šauša, Martina Iskrová-Miklošovičová
• Keywords: Deuteration, Molecule Velocity, Plateau Region, Propylene Glycol

References

[1] P. Kirkegaard, M. Eldrup, E. Mogensen and N.Y. Pedersen: Comput. Phys. Commun. Vol. 23 (1981), pp.307-335

[2] S. J. Tao: J. Chem. Phys. Vol. 56 (1972), pp.5499-5510

[3] M. Eldrup, D. Lightbody and J.N. Sherwood: Chem. Phys. Vol. 63 (1981), pp.51-58

[4] P. Bandžuch, J. Krištiak, O. Šauša and J. Zrubcová: Phys. Rev. B Vol. 61 (2000), pp.8784-8792

DOI: 10.1103/physrevb.61.8784