Relaxation Dynamics of Tryptophan in Water: A UV Fluorescence Up-Conversion and Molecular Dynamics Study

BRÄM, OLIVIER; OSKOUEI, AHMAD; TORTSHANOFF, ANDREAS; VAN MOURIK, FRANK; MADRID, MARCOS; ECHAVE, JULIAN; CANNIZZO, ANDREA; CHERGUI, MAJED

JOURNAL OF PHYSICAL CHEMISTRY A

AMER CHEMICAL SOC

Lugar: Washington; Año: 2010 vol. 114 p. 9034 - 9042

1089-5639

We report on an ultrafast experimental and simulations study of the early relaxation events of photo-excited Tryptophan in water. Experimentally, we used fluorescence up conversion in both polychromatic and single wavelength detection modes in the 300 480 nm range with polarization dependence. We report on the time evolution of the Stokes shift, bandwidth and anisotropy from tens of fs to ps. These observables contain signatures of the simultaneous occurrence of intramolecular and solvent molecule interactions, which we disentangle with the help of non-equilibrium Molecular Dynamics simulations. We also observe a breakdown of the Linear Response Approximation to describe our results.