Optimizing the Multimode Brownian Oscillator Model for the Optical Response of Carotenoids in Solution by Fine Tuning of
- PDF / 1,140,278 Bytes
- 9 Pages / 612 x 792 pts (letter) Page_size
- 40 Downloads / 186 Views
Optimizing the Multimode Brownian Oscillator Model for the Optical Response of Carotenoids in Solution by Fine Tuning of Differential Evolution R. Y. Pishchalnikov1* , A. A. Bondarenko2** , and A. A. Ashikhmin3*** (Submitted by E. E. Tyrtyshnikov) 1
2
Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, 119991 Russia Keldysh Institute of Applied Mathematics of the Russian Academy of Sciences, Moscow, 125047 Russia 3 Pushchino Scientific Center for Biological Research of Russian Academy of Sciences, Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, 142290 Russia Received April 4, 2020; revised April 20, 2020; accepted April 21, 2020
Abstract—During last twenty years, the Differential evolution algorithm (DE) has proved to be one of the powerful methods to solve minimization problems for multidimensional functions. Being a member of the family of evolutionary optimization algorithms, its main principle is based upon the concepts of natural selection and mutation. In this study, we test the potential of DE to find a proper set of parameters for the multimode Brownian oscillator model, which was then used to simulate absorption lineshapes of carotenoid molecules in solution: spheroidene and spheroidenone. This theory assumes that the correlation function of a particular electronic state of the carotenoid is calculated using the semiclassical spectral density function. Considering our previous studies on photosynthetic pigments, we employed several DE strategies to do fitting of the carotenoid experimental spectra. We found that simulated absorption spectra are very sensitive to several parameters that characterize carotenoid vibronic modes, namely, Huang–Rhys factors. Fine tuning of DE crossover parameter (Cr) and the scaling factor (F) provided acceptable convergence of the algorithm. It appears that to get good convergence of DE, a certain spectral range of carotenoid absorption from 400 to 600 nm must be chosen. This fact can be explained by the limitations of the applied theory, which simply does not predict properly the carotenoid absorption at higher frequencies. DOI: 10.1134/S1995080220080156 Keywords and phrases: differential evolution, parallel programming, carotenoids, absorption spectrum, cumulant expansion, multimode Brownian oscillator model.
1. INTRODUCTION Carotenoids are pigments that are widespread in nature [1]. They are contained in pigment-protein complexes of photosynthetic species such as plants, cyanobacteria and algae [2]. Knowing their optical properties is of extreme importance, since carotenoids participate in the primary processes of energy migration in photosynthesis and are responsible for the protection of the photosynthetic mechanism from excess incident light [3, 4]. The absorption bands of carotenoids usually peak at 400–600 nm in the visible region. That is why carotenoids are orange, red, and yellow. The basis of the chemical structure of carotenoids is a polyene hydrocarbon chain. Depending on what kind of residue terminates the p
Data Loading...
