Disorder and spectral line shapes in two-level systems

• Main Authors: Shi, Wu-Jun, Chernyak, Vladimir, Zhao, Yang, Shenai, Prathamesh M.
• Other Authors: School of Materials Science & Engineering
• Format: Article
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Materials
• Online Access: https://hdl.handle.net/10356/79639; http://hdl.handle.net/10220/19723
• Institution: Nanyang Technological University

Using a stochastic model, we examine disorder-induced changes in the absorption line shape of a chromophore embedded in a matrix of noninteracting two-level systems (TLSs) with randomly oriented dipole moments. By systematically controlling the degree of TLS positional disorder, a perfectly crystalline, glassy or a combination of the two environments is obtained. The chromophore is assumed to interact with TLSs via long-range dipole–dipole coupling. At long times and in the absence of disorder, Gaussian line shapes are found, which morph into Lorentzian for a completely disordered environment owing to strong coupling between the chromophore and a TLS in close vicinity.