Experimental Investigations on Ultrasonic Velocity and Behavior of Thermodynamic Parameters of Four Members of nO.m Series
| Periodical | Solid State Phenomena (Volumes 181 - 182) |
|---|---|
| Main Theme | Liquid Crystals and Related Materials II |
| Edited by | Yuan Ming Huang |
| Pages | 43-46 |
| DOI | 10.4028/www.scientific.net/SSP.181-182.43 |
| Citation | D. Madhavi Latha et al., 2011, Solid State Phenomena, 181-182, 43 |
| Online since | November, 2011 |
| Authors | D. Madhavi Latha, V.G.K.M. Pisipati, M. Ramakrishna Nanachara Rao, P.V. Datta Prasad |
| Keywords | Adiabatic Compressibility, nO.m Compounds, Phase Transition, Sound Velocity |
| Price | US$ 28,- |
Ultrasonic velocity measurements are carried out on four nOm compounds viz., N-(p-n-methoxy and ethoxy benzylidene)-p-n-dodecyl and tetradecyl anilines, 1O.12, 1O.14, 2O.12 and 2O.14. The first three compounds exhibit mono variant nematic phase while the last compound exhibits nematic and smectic-A phases with variable thermal ranges. The temperature dependence of sound velocity, U shows minima at the isotropic-nematic and nematic-smectic-A transitions. In conjunction with the density data of these compounds, the thermo acoustic parameters such as adiabatic compressibility (βad), the molar sound velocity (Rao’s number) (Rn), molar compressibility (W), molecular free length (Lf) and available volume (Va) are estimated. In addition the intermolecular free length (Lf) is estimated in three different ways employing density and ultrasonic velocity data. The results are compared with the data available in literature of other compounds.
