ELASTIC, PIEZOELECTRIC AND DIELECTRIC-CONSTANTS OF PENTAERYTHRITOL

The elastic, piezoelectric and dielectric constants of pentaerythritol , C(CH2OH)(4), have been computed employing the method of long waves a nd the unscreened rigid ion potential model developed by RAMAMOORTHY a nd KRISHNAMURTHY. Piezoelectric contribution is taken into account in the computation of elastic constants. This is the first report on the piezoelectric and dielectric constants of pentaerythritol. In the nota tions followed by LANDOLT-BORNSTEIN the computed piezoelectric constan ts are: g(14) = 4.82, g(15) = 4.37: g(31) = 16.21 and g(36) = 5.89 (in unit of 10(-3) Vm/N) and the static dielectric constants are: K-1 = 2 .38 and K-3 = 2.47. The hydrogen bonding in pentaerythritol has no eff ect on its dielectric behaviour. Calculation of acoustic velocities in piezoelectric crystals and as a special case to the crystals of class 4 is explained in detail. Sound velocities calculated from the elasti c, piezoelectric and dielectric constants computed in the present inve stigation agree with the experimental values determined by the ultraso nic method.