טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentVolkovich Roie
SubjectNumerical Studies of Thermal Effects in Electron Transfer
Through Molecular Bridges
DepartmentDepartment of Chemistry
Supervisor Professor Uri Peskin
Full Thesis textFull thesis text - English Version


Abstract

In this thesis we introduce a model for electron transfer in symmetric donor-bridge-acceptor (DBA) complexes with electronic coupling to nuclear bridge modes, using the Redfield formulation. We investigate the effect of a thermal bath on the electronic dynamics in terms of the bath temperature, spectral density and the electronic nuclear coupling strength for tunneling through the bridge. We study the validity of Redfield simulation and we demonstrate that the transport mechanism through the molecular bridge is controlled by the location of the electronic nuclear coupling term along the bridge. As the electronic nuclear coupling term is shifted from the donor/acceptor-bridge contact sites into the inner bridge sites, the mechanism changes from kinetic transport (incoherent, thermally activated, bridge-length independent) to coherent tunneling oscillations. We introduce a kinetic scheme for defining rate constants in the kinetic regime. This study joins earlier works aiming to explore the factors which control the mechanism of electronic transport through molecular bridges and molecular wires.  We show that even local coupling to the thermal bath can induce pure dephasing leading to coherent mechanism.