The specific heat of simple liquids
The specific heat of simple liquids
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DOI：
10.1016/s0022-3093(02)01498-9
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发表时间：
2002-09-01
影响因子：
3.5
通讯作者：
Granato, AV
中科院分区：
文献类型：
--
作者：
Granato, AV
比热应该是计算液体的最简单的性质，因为它需要的假设最少。它的预言为任何凝聚态理论提供了必要的检验。从标准教科书中，我们习惯于用简单的模型给出气体和晶体比热的大小和温度依赖性的定量结果，但不包括液体。非线性理论提供了这样一个模型，统一了结晶态、液态和玻璃态。根据该理论，简单液体是在热平衡时含有几个百分比的结晶体，而玻璃是冻结的液体。相对于晶态，对液态比热的贡献主要有两个：正的结构项和负的非谐项。对于温度为T-m < T < T-c的正常稳定液体，其中T-m为熔化温度，T-c为临界温度，非谐项在高温下占主导地位。对于在T-g < T < T-m范围内的过冷液体，其中T-g是玻璃化温度，结构组分在低温下占主导地位。在T-g，Δ C（v）迅速下降到零。对于T < T-g的冻结液体，由于超导隧穿、德拜θ变化和由超导共振模激发产生的玻色子峰，存在低温异常。
The specific heat should be the simplest property of a liquid to calculate because it requires the fewest assumptions. Its prediction provides a necessary test for any theory of condensed matter. We are accustomed, from standard textbooks, to having simple models giving quantitative results for the magnitude and temperature dependence of the specific heat of gases and crystals, but not for liquids. The interstitialcy theory provides such a model, unifying crystalline, liquid and glassy states. According to the theory, simple liquids are crystals containing a few percent of interstitialcies in thermal equilibrium, and glasses are frozen liquids. Relative to the crystalline state, there are two principal contributions to the specific heat of the liquid state, a positive structural term and a negative anharmonic term. For normal stable liquids at temperatures T-m < T < T-c where T-m is the melting and T-c the critical temperature, the anharmonic term dominates at high temperatures. For supercooled liquids in the range T-g < T < T-m, where T-g is the glass temperature, the structural component dominates at low temperatures. At T-g, there is a rapid decrease to zero of deltaC(v). For frozen liquids at T < T-g there are low temperature anomalies due to interstitialcy tunneling, a Debye theta change, and a Boson peak arising from excitations of interstitiatcy resonant modes.