| Spectral analysis is an effective method which can quickly and accurately detect the composition and content of substances,so it is widely used in engineering practice.With the development of computer technology,it is more convenient to explore the structure and spectral characteristics of molecular system by using quantum chemical method,so it has developed rapidly in the field of optical engineering.Among many quantum chemistry calculation methods,fully random conformational search method based on Monte Carlo can ensure that all possible structures of molecular system are obtained without any additional restrictions.Then combined with the calculation process of configuration optimization,high-level single-point energy calculation and basis set superposition error correction,the results are sorted and analyzed,and finally the representative structure of molecular system is obtained.It is very important to obtain the stable structure and spectral information for the analysis of molecular composition,structural characteristics,properties and functions.By using this method,we can successfully study the space structure of biomolecules,the microscopic interaction and spectral properties between solute molecules and solvent molecules in solution environment.The main contents of this paper are as follows:1.The spatial structure characteristics of glucose molecules are studied by using fully random conformational search method based on Monte Carlo.The difference between this method and traditional research method is that the initial structure generation process is more random and comprehensive,so the accuracy of the results is ensured.In this method,all the possible structures obtained by fully random conformational search are calculated by quantum chemistry,and then the results are analyzed and sorted out.Finally,two representative configurations Glc A and Glc B of glucose molecule are obtained.The structure and spectral vibration characteristics of the two representative configurations are compared with spectral analysis.2.Based on the structure and spectral characteristics of glucose in gas phase,the hydration structure of glucose is discussed,and the first hydration shell structure model of glucose is studied.It is found that Glc·（H2O）n-1 and Glc·（H2O）n（n = 1 ～ 15）are related in structure by comparison.Therefore,On the basis of the most stable representative configuration of Glc·（H2O）n-1,a method of generating the stability representative configuration of Glc·（H2O）n by fully random conformational search is proposed,and a complete first hydration shell structure model of glucose is finally established.The characteristics of different water solution models are determined by analyzing the Raman vibration characteristics of glucose under CPCM model（Conductor-like Polarizable Continuum Model）,the first hydration shell of glucose in the gas phase,and the first hydration shell of glucose under the CPCM model.3.On the basis of the study of the first hydration shell of glucose and the characteristics of the hydrate sites of glucose molecule,we study the structural characteristics of the hydration structure of cellobiose.We add water molecules randomly to different hydrate sites to form all possible hydration structures,and then determine the representative configurations of Cel A·（H2O）n（n=1～18）in each stage according to quantum chemical calculation theory,and finally establish the complete first hydration shell of cellobiose.The molecular vibration of the structure is studied by spectral analysis.This paper mainly studies the space structure of glucose,the first hydration shell structure of glucose and the first hydration shell structure of cellobiose.Through repeated analysis and verification,we have determined the method to study the molecular system structure and the micro-interaction between molecules.The establishment of this research method makes the research of biomolecular space structure and solution model more convenient.In the practical application of life,the research method also has a great role,such as in the field of scientific research,medical pathology research,drug research and development,as well as the prediction of disease occurrence and treatment and so on. |
