  In this paper we present CTRAMER (Charge Transfer RAtes from Molecular
dynamics, Electronic structure, and Rate theory), an open source software
package for calculating interfacial charge transfer (CT) rate constants in
organic photovoltaic (OPV) materials based on ab initio calculations and
molecular dynamics simulations. The software is based on identifying
representative donor acceptor geometries within interfacial structures obtained
from molecular dynamics simulation of donor acceptor blends and calculating the
corresponding Fermi s golden rule CT rate constants within the framework of the
linearized semiclassical approximation. While the methods used are well
established, the integration of these state of the art ideas from different
disciplines to study photoinduced CT between excited states and explicit
environment, in our opinion, makes this package unique and innovative. The
software also provides tools for plotting other observables of interest. After
outlining the features and implementation details, usage and performance of the
software are demonstrated with results from an example OPV system.
