老师课件材料热力学第七章.pdf

第六章 （2） Statistical Thermodynamics 任课 ： 材料科学与工程系 Introduction ⚫ Partition Function and the Internal Energy U ⚫ Microscopic View of Entropy ⚫ Connecting Macroscopic and Microscopic Thermodynamics ⚫ Multimode Partition Functions ⚫ The Einstein Model of a Crystal ⚫ Ensemble Theory Partition Function and the Internal Energy U ⚫ 建立宏观量与微观量的联系：统计力学的方法 ⚫ 统计方法及宏观量—统计力学的等效原理 1、时间平均统计方法 2、状态平均统计方法 3、系综平均统计方法 Partition Function and the Internal Energy U Partition Function and the Internal Energy U Partition Function and the Internal Energy U Partition Function and the Internal Energy U Partition Function and the Internal Energy U Partition Function and the Internal Energy U Partition Function and the Internal Energy U Partition Function and the Internal Energy U Partition Function and the Internal Energy U Partition Function and the Internal Energy U Partition Function and the Internal Energy U Microscopic View of Entropy Microscopic View of Entropy Microscopic View of Entropy ⚫ Macroscopic treatment of finding equilibrium we ized the entropy of the isolated system which constrained us to constant total U, N and V. ⚫ Here in our microscopic treatment of finding equilibrium, which is the most likely macrostate, we have the same constraints on U and N. But what about the constraint of constant volume? Actually, we already used it to find the most probable distribution. Allowed variations in the populations, not change in the energies of energy level. Constant volume Connecting Macroscopic and Microscopic Thermodynamics Connecting Macroscopic and Microscopic Thermodynamics Connecting Macroscopic and Microscopic Thermodynamics Connecting Macroscopic and Microscopic Thermodynamics Connecting Macroscopic and Microscopic Thermodynamics