Laird, Brian BostianThompson, Ward H.2014-12-162014-12-162011-08-26Laird, Brian Bostian; Thompson, Ward H. (2011). "Time-dependent fluorescence in nanoconfined solvents: Linear-response approximations and Gaussian statistics. The Journal of Chemical Physics, 135(8):084511. http://dx.doi.org/10.1063/1.36268250021-9606https://hdl.handle.net/1808/16128This is the publisher's version, also available electronically from http://scitation.aip.org/content/aip/journal/jcp/135/8/10.1063/1.3626825.The time-dependent fluorescence of a model dye molecule in a nanoconfined solvent is used to test approximations based on the dynamic and static linear-response theories and the assumption of Gaussian statistics. Specifically, the results of nonequilibrium molecular-dynamics simulations are compared to approximate expressions involving time correlation functions obtained from equilibrium simulations. Solvation dynamics of a model diatomic dye molecule dissolved in acetonitrile confined in a spherical hydrophobic cavity of radius 12, 15, and 20 Å is used as the test case. Both the time-dependent fluorescence energy, expressed as the normalized dynamic Stokes shift, and the time-dependent position of the dye molecule after excitation are examined. While the dynamic linear-response approximation fails to describe key aspects of the solvation dynamics, assuming Gaussian statistics reproduces the full nonequilibrium simulations well. The implications of these results are discussed.Article10.1063/1.3626825openAccess