Probing the Conformations of Single Molecule via Photon Counting Statistics

We suggest an approach to detect the conformation of single molecule by using the photon counting statistics. The generalized Smoluchoswki equation is employed to describe the dynamical process of conformational change of single molecule. The resonant trajectories of the emission photon numbers $<N >$ and the Mandel's $Q$ parameter, in the space of conformational coordinates $\bm{\mathcal{X}}$ and frequency $\omega_L$ of external field ($\bm{\mathcal{X}}-\omega_L$ space), can be used to rebuild the conformation of the single molecule. As an example, we consider Thioflavin T molecule. It demonstrates that the results of conformations extracted by employing the photon counting statistics is excellent agreement with the results of {\it ab initio} computation.