Statistical fine structure in the inhomogeneously broadened electronic origin of pentacene inphyphen;terphenyl

摘要

Recently, the first observation of statistical fine structure on an inhomogeneously broadened absorption profile was reported lsqb;W. E. Moerner and T. P. Carter, Phys. Rev. Lett.59, 2705 (1987)rsqb; for mixed crystals of pentacene inphyphen;terphenyl using laser frequencyhyphen;modulation spectroscopy. Statistical fine structure is timehyphen;independent structure on the inhomogeneous line caused by statistical variations in the spectral density of absorbers in each frequency interval. In this work, a model and an analysis of statistical fine structure using autocorrelation techniques are presented, and the dependence of the effect for pentacene inphyphen;terphenyl at 1.4 K on modulating frequency, detection phase, center concentration, and position in the sample is described. Statistical fine structure provides a new method for probing inhomogeneous systems that allows investigation of the underlying probability distribution function and the determination of the homogeneous linewidth. This fine structure also represents a fundamental limit on the detectability of shallow spectral features in inhomogeneously broadened lines.