Theoretical studies of short polyproline systems: recalibration of a molecular ruler.

FRET experiments enable studies of the chemical and physical properties of individual molecules, which has long been a dream of chemists. However, these modern experimental techniques are still limited by the lack of information about the dynamic behavior of the fluorescent labels as well as by the use of dipole-dipole approximation even at short donor-to-acceptor distances. Our results help to suggest that these assumptions need to be carefully considered when designing experiments.

Energy transfer in the nanostar: the role of coulombic coupling and dynamics.

We present a theoretical investigation of energy transfer in the phenylene ethynelene dendrimer known as the nanostar. Data from extensive molecular dynamics simulations are used to model the dynamical effects caused by torsional motion of the phenyl groups. We compare rate constants for energy transfer between the two-ring chromophore and the three-ring chromophore obtained via the Förster model, the ideal dipole approximation (IDA), and the transition density cube (TDC) method, which has as its limit an exact representation of the Coulombic coupling.