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Electric-field effects of two-level systems observed with single-molecule spectroscopy

2003; American Institute of Physics; Volume: 118; Issue: 20 Linguagem: Inglês

10.1063/1.1574789

1520-9032

M. Bauer, L. Kador,

Molecular Junctions and Nanostructures

The fluorescence excitation spectra of single chromophores in a solid often consist of several components at low temperature, which is due to the interaction with matrix two-level systems (TLSs). For a number of terrylene molecules in n-hexadecane we observed electric-field-induced changes of the intensity and splitting of the spectral components. With some basic assumptions the data allow us to calculate all the characteristic parameters of a single TLS, viz., the (zero field) asymmetry, the tunnel parameter, and the permanent electric dipole moment. In one case we found an exceptionally large dipole moment of about 8 Debye.