Chiroptical Symmetry Analysis: Exciton Chirality-Based Formulae to Understand the Chiroptical Responses of Cn and Dn Symmetric Systems

The high sensitivity of chiroptical responses to conformational changes and supramolecular interactions has prompted an increasing interest in the development of chiroptical applications. However, prediction of and understanding the chiroptical responses of the necessary large systems may not be affordable for calculations at high levels of theory. In order to facilitate the development of chiroptical applications, methodologies capable of evaluating the chiroptical responses of large systems are necessary. The exciton chirality method has been extensively used for the interaction between two independent chromophores through the Davydov model. For systems presenting C2 or D2 symmetry, one can get the same results by applying the selection rules. In the present article, the analysis of the selection rules for systems with symmetries Cn and Dn with n = 3 and 4 is used to uncover the origin of their chiroptical responses. We foresee that the use of the Chiroptical Symmetry Analysis (CSA) for systems presenting the symmetries explored herein, as well as for systems presenting higher symmetries will serve as a useful tool for the development of chiroptical applications.

Chiroptical Symmetry Analysis (CSA): Exciton Chirality-Based Formulae to Understand the Chiroptical Responses of Cn and Dn Symmetric Systems

The high sensitivity of chiroptical responses to conformational changes and supramolecular interactions has prompted an increasing interest in the development of chiroptical applications. However, prediction and understanding the chiroptical responses of the necessary large systems may not be affordable for calculations at high levels of theory. In order to facilitate the development of chiroptical applications, methodologies capable of evaluating the chiroptical responses of large systems are necessary. Exciton chirality method has been extensively used for the interaction between two independent chromophores through the Davydov model. For systems presenting C2 or D2 symmetry one can get to the same results by applying the selection rules. In the present article, analysis of the selection rules for systems with symmetries Cn and Dn with n = 3 and 4 is used to uncover the origin of their chiroptical responses. We hope that the use of the chiroptical symmetry analysis (CSA) for systems presenting the symmetries explored herein as well as for systems presenting higher symmetries will serve as a useful tool for the development of chiroptical applications.

Chiroptical Symmetry Analysis (CSA): on the Way from the Understanding of Highly Symmetric Systems to the Development of Chiroptical Applications

The high sensitivity of chiroptical responses to conformational changes and supramolecular interactions has prompted an increasing interest in the development of chiroptical applications. However, prediction and understanding the chiroptical responses of the necessary large systems may not be affordable for calculations at high levels of theory. In order to facilitate the development of chiroptical applications, methodologies capable of evaluating the chiroptical responses of large systems are necessary. Exciton chirality method has been extensively used for the interaction between two independent chromophores through the Davydov model. For systems presenting C2 or D2 symmetry one can get to the same results by applying the selection rules. In the present article, analysis of the selection rules for systems with symmetries Cn and Dn with n = 3 and 4 is used to uncover the origin of their chiroptical responses. We hope that the use of the chiroptical symmetry analysis (CSA) for systems presenting the symmetries explored herein as well as for systems presenting higher symmetries will serve as a useful tool for the development of chiroptical applications.

Analytical study on the generalized Davydov model in the alpha helical proteins

In this paper, we investigate the dynamics of a generalized Davydov model derived from an infinite chain of alpha helical protein molecules which contain three hydrogen bonding spines running almost parallel to the helical axis. Through the introduction of the auxiliary function, the bilinear form, one-, two- and three-soliton solutions for the generalized Davydov model are obtained firstly. Propagation and interactions of solitons have been investigated analytically and graphically. The amplitude of the soliton is only related to the complex parameter [Formula: see text] and real parameter [Formula: see text] with a range of [Formula: see text]. The velocity of the soliton is only related to the complex parameter [Formula: see text], real parameter [Formula: see text], lattice parameter [Formula: see text], and physical parameters [Formula: see text], [Formula: see text] and [Formula: see text]. Overtaking and head-on interactions of two and three solitons are presented. The common in the interactions of three solitons is the directions of the solitons change after the interactions. The soliton derived in this paper is expected to have potential applications in the alpha helical proteins.

THERMAL STABILITY OF THE NEW SOLITON TRANSPORTED BIO-ENERGY UNDER INFLUENCE OF FLUCTUATIONS OF CHARACTERISTIC PARAMETERS AT BIOLOGICAL TEMPERATURE IN THE PROTEIN MOLECULES

The dynamic behaviors of the new soliton in the improved Davydov model in the protein molecules at biological temperature have been numerically simulated by utilizing the dynamic equations for the bio-energy transport and the Runge–Kutta way. In this simulation the influences of the temperature and structure disorders of the protein molecules on the soliton transporting the bio-energy have been completely considered. We find that the new soliton is quite stable in the cases of motion of a long time of 300 ps and of disorders of the structures of the proteins at biological temperatures of 300 K–320 K. The disorders of the structures contain the disorder of mass sequence of amino acids and the fluctuations of the coupling constant, force constant and dipole- dipole interaction constant and ground state energy of the proteins, designating the features of its structure and interactions between the particles in it. However, the soliton disperses in the cases of higher temperature of 325 K and larger structure disorders. The numerical results show that the new soliton is very robust against the influences of the thermal perturbation and structure disorders at biological temperature 300 K, its lifetime and critical temperature are at least 300 ps at 300 K and 320 K, respectively. These results are also consistent with analytical data.