Acene Molecules Research Articles

Stochastic mechanical approach to electron transfer in acene molecules

By using stochastic mechanical simulations, we numerically investigate electron transfers in oligoacenes (anthracene, tetracene and pentacene). These π-conjugated oligomers are applied to organic devices and the performance depends on the electronic transfer properties. From quantum mechanical or quantum chemical calculations, estimation of the transport properties have been so far discussed via transfer integrals. Stochastic mechanics provide the quantum motion of electrons from the wave functions. From the analysis of the quantum motion of electrons, we calculate some dynamical properties, such as mean-square displacement relating with the mobility and the electron transfer rate between two anthracenes. Our dynamical approach is efficient and practical and especially important for analysis of molecular or nanoscale devices.

Calculation and analysis of the excited states and fine structure of vibronic spectra of anthracene, anthracene-d 10, and tetracene

Structural dynamic models of the excited states of some molecules of the acene series (anthracene, anthracene-d10, and tetracene) have been developed and the vibronic structure of the fluorescence and absorption spectra of these molecules has been calculated by the parametric method of the theory of vibronic spectra. Good agreement is obtained between the calculated and experimental spectra. It is shown that the system of parameters determined for these acenes in the second-order approximation of the method is highly transferable in the acene series. The models proposed adequately describe the real structure of the excited molecules and make it possible to predict quantitatively the fine vibrational structure of the spectra, including relatively weak effects (weak bands, the spectral variations in the series of these molecules, and the variations upon deuterium substitution). The specific features of the structural variations in the investigated acene molecules upon their excitation and the dynamics of these variations in the series of these molecules are studied.