Vibrational spectrum of solid picene (C_22H_14)

TL;DR

This paper combines experimental and ab-initio methods to analyze the vibrational spectrum of solid picene, identifying modes that may influence its superconducting properties upon doping.

Contribution

It provides the first unambiguous assignment of vibrational modes in solid picene, linking specific modes to potential electron coupling relevant for superconductivity.

Findings

Identified vibrational modes strongly coupled to electrons.

Provided a comprehensive Raman and infrared spectral assignment.

Highlighted modes potentially responsible for superconductivity.

Abstract

Recently, Mitsuhashi et al., have observed superconductivity with transition temperature up to 18 K in potassium doped picene (C22H14), a polycyclic aromatic hydrocarbon compound [Nature 464 (2010) 76]. Theoretical analysis indicate the importance of electron-phonon coupling in the superconducting mechanisms of these systems, with different emphasis on inter- and intra-molecular vibrations, depending on the approximations used. Here we present a combined experimental and ab-initio study of the Raman and infrared spectrum of undoped solid picene, which allows us to unanbiguously assign the vibrational modes. This combined study enables the identification of the modes which couple strongly to electrons and hence can play an important role in the superconducting properties of the doped samples.