大学化学 >> 2026, Vol. 41 >> Issue (6): 92-99.doi: 10.12461/PKU.DXHX202511181

所属专题： 化学“101计划”案例

专题 上一篇    

量子统计热力学方法分析液态和气态热容关系

徐子豪, 姚加, 彭笑刚   

  1. 浙江大学化学系, 浙江 杭州 310058
  • 收稿日期:2025-11-25 录用日期:2025-12-29 发布日期:2026-06-18
  • 通讯作者: 姚加, 彭笑刚 E-mail:yaojia@zju.edu.cn;xpeng@zju.edu.cn Jia Yao, Xiaogang Peng
  • 基金资助:
    高等教育质量保障专项(化学“101计划”专项)；教育部基础学科拔尖学生培养计划2.0研究课题(20222097)

Statistical thermodynamics of heat capacity of liquid and gas

Zihao Xu, Jia Yao, Xiaogang Peng   

  1. Department of Chemistry, Zhejiang University, Hangzhou 310058, Zhejiang Province, China
  • Received:2025-11-25 Accepted:2025-12-29 Published:2026-06-18
  • Contact: Jia Yao, Xiaogang Peng E-mail:yaojia@zju.edu.cn;xpeng@zju.edu.cn

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摘要： 理想气体摩尔热容可用量子统计热力学定量计算。但液态量子自由度难以确定，目前尚无方法直接从统计热力学计算液态摩尔热容。气态到液态的相变对分子内振动影响有限，只是把气态分子的自由平动和转动自由度转化为类振动自由度。于是，液态物质的摩尔热容可定量关联相应气态的摩尔热容，根据量子自由度演化而算得。

关键词: 液态, 自由度转化, 热容, 量子统计热力学

Abstract: The molar heat capacity of ideal gas can be quantitatively calculated using quantum statistical thermodynamics. However, due to difficulty on determining degrees of freedom in liquid state, there is currently no method for directly computing the molar heat capacity of liquids. We noticed that the phase transition from gas to liquid has a limited effect on intramolecular vibrations, but converting the free translational and rotational degrees of freedom of gas molecules into quasi-vibrational degrees of freedom with very low frequency. Therefore, the molar heat capacity of a liquid can be quantitatively correlated with the molar heat capacity of the corresponding gas, calculated on the basis of evolution of quantum degrees of freedom.

Key words: Liquid, Transformation of motion, Heat capacity, Quantum statistical thermodynamics