大学物理 ›› 2026, Vol. 45 ›› Issue (4): 87-.doi: 10.16854/j.cnki.1000-0712.250299

• 大学生园地 • 上一篇    下一篇

玻尔兹曼、费米及玻色分布下理想气体的平均相对速率

黄金龙,李宁,王菲,胡海云,张用友   

  1. 1. 北京理工大学 物理学院,北京100081;2. 华北电力大学 数理学院,北京102206 
  • 收稿日期:2025-06-03 修回日期:2025-09-16 出版日期:2026-07-06 发布日期:2026-08-03
  • 作者简介:黄金龙(2005—),男,新疆伊宁人,北京理工大学强基物理班2023级本科生.
  • 基金资助:
    国家自然科学基金(12074037)资助

Average relative speed of ideal gases under Boltzmann, Fermi, and Bose distributions#br#

HUANG Jin-long, LI Ning, WANG Fei, HU Hai-yun , ZHANG Yong-you   

  1. 1. School of Physics, Beijing Institute of Technology, Beijing 100081, China;
    2. School of Mathematics and Science, North China Electric Power University, Beijing 102206, China
  • Received:2025-06-03 Revised:2025-09-16 Online:2026-07-06 Published:2026-08-03

摘要: 气体分子平均相对速率是理解气体输运性质的核心物理量. 本文针对理想气体,系统推导了三种常见统计分布即玻尔兹曼分布、费米分布及玻色分布下的气体平均相对速率表达式. 对于玻尔兹曼分布也即麦克斯韦分布,严格给出平均相对速率解析解. 在绝对零度下,理想费米气体的平均相对速率和平均速率分别为u=3635vF和v=34vF(vF为费米速率),而理想玻色气体的平均相对速率和平均速率均为0. 在非零温下,它们则需通过数值积分求解. 计算结果表明平均相对速率和平均速率完全由速度分布律决定,这为气体动理论相关的热学教学提供了重要补充. 


关键词: 平均相对速率, 理想气体, 玻尔兹曼分布, 费米分布, 玻色分布 

Abstract:

The average relative speed of gas molecules is a core physical quantity for understanding the transport properties of gases. This work derives expressions for the average relative speed of ideal gases under three common statistical distributions—Boltzmann, Fermi, and Bose distributions. For the Boltzmann distribution, corresponding to Maxwell distribution, the analytical solution of the average relative speed is rigorously derived. At absolute zero temperature, the average relative speed and average speed of an ideal Fermi gas are u=3635vF and v=34vF (vF is the Fermi rate), respectively, while both the average relative speed and average speed of an ideal Bose gas are zero. At non-zero temperatures, these quantities need to be solved via numerical integration. Calculation results show that the average relative speed and average speed are entirely determined by the velocity distribution law, which provides an important supplement to thermal physics teaching related to the kinetic theory of gases.


Key words: average relative rate, ideal gas, Boltzmann distribution, Fermi distribution, Bose distribution