Theoretical Research On Atomic Potential Energy And Thermodynamic Function With Temperature Change

Potential energy function, binding energy, specific heat, thermal expansioncoefficient and other physical quantities are external embodiment of macroscopicphysical properties, when it occurs chemical change between internal microscopicmolecular and atoms in solid. It is not only the basis of solid materials, but also aimportant subject in condensed matter physics.This thesis mainly studies the properties of ferromagnetic metal. There is a closerelationship between material heat capacity, thermal expansion coefficient and theirexternal conditions, such as pressure, humidity, temperature and so on. The effect oftemperature is considered, which contributes to metallic potential, binding energy,specific heat, and thermal expansion coefficient, starting from the modified latticeequation, the paper makes a detailed analysis on coupling magnetic electron numberdensity which is related to temperature, and calculates the first derivative algebraic ofthe coupling magnetic electron number density. Meanwhile, it discusses thethermodynamic properties at low temperature and Curie temperature respectively.From the viewpoint of the theoretical derivation, first of all, the thesis calculates thevalue of bond length, bond energy around each atom in the nearest neighbor, thesecond neighbor of face-centered cubic and body centered cubic crystal according tothe valence bond theory. So here we only consider the nearest neighbor, the secondneighbor atomic and their potential energy, cohesive energy and so on. Using OAtheory, we have made a detailed description to the lattice modified coefficient, andtake the first derivation to it, the analytic expression of linear thermal expansioncoefficient and specific heat is obtained. This paper establishes a simple mathematicalmodel to theoretical calculation and derivation to solve the coupling magneticelectron number density function by taking Taylor series expansion of transcendentalequation and its approximate solution. On this basis, we also use Mathematicasoftware to obtain the Inverse function of electron number density and make it adetailed analysis. While taking higher order approximation of the function, we makeanalysis to the fourth and five order solution, finding the error is less than5%, which is in line with the requirements of error range. To the ferromagnetic metal, it isconsistent with the corresponding experiment and theory.