Modern Methods in the Theory of Many-Phonon Processes

Optical line shapes for polymethine dyes and their aggregates: Novel theory of quantum transitions and its correlation with experiment

“…The peak degrades as dozy chaos increases and is absorbed by the Gauss-like wing of the line. The result is the same as that ensues from the standard LandauZener [12,13] theory of quantum transitions [14][15][16][17][18][19][20][21][22][23][24]. Thus, the standard theory of quantum transitions is a limiting case of the novel theory of quantum transitions at large dozy chaos.…”

“…This assumption answers to the classical motion of reorganization of nuclei in the nearby environment [21][22][23][24]. The novel theory of quantum transitions [4] considers the general case of nuclear reorganization motion, i.e., quantum reorganization of nuclei where their motion is inseparable from that of an electron.…”

Motional narrowing of broadband absorption of solvatochromic indicator Betaine 30

“…Linear and quadratic EPC processes can only enhance the homogeneous spectral width with rising T. In the harmonic singlemode approximation at the high-temperature limit, the EPC theories predict broadening as T 1/2 [11,12] and T 2 [13,14], for the first-order and second-order processes, respectively. Alternatively, for the possible causes of narrowing one should consider the T dependence of inhomogeneous width.…”

“…In contrast to extensively studied peak maxima, the bandwidths have rarely been considered, and theoretical models of electron-phonon coupling (EPC) applied [9,10]. The scarcity of width data is surprising, bearing in mind that broadening studies usually prevail in the solid-state impurity spectroscopy of multiphonon bands, such as F-centers [11,12], or zero phonon transitions [13,14]. The analysis of broadening in terms of EPC theories is believed to be more straightforward than that of the spectral shift, because the former is less influenced by thermal expansion of the matrix.…”

Dynamic electron localization initiated by particle-bath coupling

“…Such a quasi-classical description has been used to analyze multiphonon trapping on an impurity center, in a semiconductor, and self-trapping of carriers and excitons 34,35 . This approach has also been used in the past and proved to be effective in the limit of strong electron-phonon coupling [36][37][38] . It was shown that in the Froehlich polaron model, the strong coupling expansion is well suited to describe the optical conductivity 34 .…”