This article introduces a procedure for modelling of large structures using a structural approach usually referred to as a bond-valence method. This empirical method minimalizes the computation costs and facilitates the contruction of complex 3D images of thermally dependent electron density even for very large periodic structures. This method also provides a convenient way to visualize the carrier density, defect locations, and valence dynamics under thermal fluctuation. | VNU Journal of Science: Mathematics – Physics, Vol. 34, No. 3 (2018) 85-89 Valence Illustration for Large Structure: A Fast Empirical Approach Based on Bond-Valence Method Hoang Nam Nhat* Faculty of Engineering Physics and Nanotechnology, VNU University of Engineering and Technology, E4 Building, 144 Xuan Thuy, Cau Giay, Hanoi, Vietnam Received 18 September 2018 Accepted 24 September 2018 Abstract: Modelling of large structures by using the quantum-mechanical approach is still not accessible, especially for many heavy atoms complexes, as these tasks require vast computational resources that are not often available. This article introduces a procedure for modelling of large structures using a structural approach usually referred to as a bond-valence method. This empirical method minimalizes the computation costs and facilitates the contruction of complex 3D images of thermally dependent electron density even for very large periodic structures. This method also provides a convenient way to visualize the carrier density, defect locations, and valence dynamics under thermal fluctuation. Keywords: Bond-valence, defects, modelling, tools. 1. Introduction The reconstruction of electric field gradient and valence structure plays an important role in understanding the properties of materials at microscopic level. Unfortunately, the modelling illustration is not available for many large structures due to complexity in computation. As known, there are many different field-dependent gradient-based methods for illustration purposes but one among the most efficient ones is a method called a bond-valence method, which was proposed by I. D. Brown [1] decades ago. As this method requires an a priori known crystal structure of materials - the information that was not often available for many compounds in the past, its application was limited to some simple structures and metalo-organic compounds where such data are accessible. The recent renaissance of this method follows from .
