Accession Number : ADA212688


Title :   Optical Detection and Probing of Single Dopant Molecules of Pentacene in a p-Terphenyl Crystal by Means of Absorption Spectroscopy


Descriptive Note : Interim rept.


Corporate Author : IBM ALMADEN RESEARCH CENTER SAN JOSE CA


Personal Author(s) : Kador, L ; Horne, D E ; Moerner, W E


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a212688.pdf


Report Date : 31 Aug 1989


Pagination or Media Count : 56


Abstract : Optical absorption lines of impurity molecules or ions in a solid matrix are usually subject to inhomogeneous broadening, thereby reflecting various imperfections in the structure of the host material. The inhomogeneous distribution can be roughly described by a Gaussian profile. A fundamental statistical fine structure (SFS) is superimposed on the smooth Gaussian curve. Using a combination of laser frequency-modulation absorption spectroscopy and either Stark, longitudinal ultrasonic, or transverse ultrasonic internal modulation, the optical absorption spectrum of a single impurity molecule of pentacene in p-terphenyl crystal may be measured at liquid helium temperatures. The general properties of this detection method are illustrated by first applying the technique to the detection of persistent spectral holes in the pentancene/p-terphenyl system. Selection of a single absorber for-measurement is accomplished by tuning the probing laser far out into the wings fo the inhomogeneously broadened 0-0 absorption lines for either the 0(1) or 0(2) sites. The single-molecule line shape is similar to that predicted by a simple model of the double-modulation process. The approximate amplitude of the single- molecule signals suggests that triplet bottleneck power broadening is suppressed for out in the wings of the inhomogenous line. This work probes the ultimate N=1 limit of the statistical fine structure present in all inhomogenous absorption lines.


Descriptors :   *BENZENE COMPOUNDS , *IMPURITIES , *ANTHRACENES , *PHENYL RADICALS , *DOPING , *CRYSTALS , MOLECULES , MATERIALS , STATISTICS , OXYGEN , SPECTRA , ULTRASONICS , HOLES(OPENINGS) , CRYSTAL DEFECTS , INTERNAL , TUNING , VISIBLE SPECTRA , ABSORPTION SPECTRA , WINGS , MODULATION , AMPLITUDE , STARK EFFECT , CYCLIC COMPOUNDS , HOMOGENEITY , SPECTRAL LINES , TRANSVERSE , LINE SPECTRA , LIQUID HELIUM , SPECTROSCOPY , OPTICAL DETECTION , DETECTION , TEMPERATURE , PROBES , IONS , OPTICAL PROPERTIES


Subject Categories : Organic Chemistry
      Physical Chemistry
      Crystallography


Distribution Statement : APPROVED FOR PUBLIC RELEASE