Calculation and Measurement of the Effect of Pressure on Charge Carrier Transport in Naphthalene

Abstract

Intermolecular transfer integrals, including exchange and vibrational effects, for an excess electron and an excess hole in a naphthalene crystal are calculated as functions of pressure using the linear compressibilities. These integrals are then used to calculate the pressure dependence of the band structure, the drift mobility components and the Hall mobility.

A novel design of a non-magnetic high pressure cell with optical windows is described. Hall mobility of an excess hole was measured at high pressure by a photo-injection technique. The results of the calculations give a good agreement with available drift mobility data and with the Hall mobility measured in this work. Comparison between the calculated and observed mobilities shows that the constant mean-free-path approximation is superior to the constant-relaxation-time approximation for naphthalene.