Multiple Fano effect in charge density wave systems

A general framework for analyzing the multiple Fano effect (MFE) in charge density wave (CDW) systems is developed. The MFE occurs when IR active modes have frequencies above the CDW gap and interference between the IR modes and the electronic continuum leads to a series of resonances and anti-resonances. We parameterize the peaks and dips of the absorption by a set of bare frequencies, a pinning parameter and one interaction parameter. We apply this method to recently observed photoinduced absorption spectra of π-conjugated polymer films.