Nuclear liquid-gas phase transitions are investigated in the framework of static antisymmetrized molecular dynamics (static AMD) model under either a constant volume or a constant pressure. A deuteron quadrupole momentum fluctuation thermometer is applied to extract the temperature of fragmenting systems of ³⁶Ar and ¹⁰⁰Sn. A plateau structure of caloric curves is observed under a constant volume for those system with a density ρ ⩽ 0.03 fm⁻³. A clear backbending in the caloric curves, which indicates a first order phase transition, is observed under a constant pressure with all pressures studied. The similar behavior of caloric curves of ³⁶Ar and ¹⁰⁰Sn systems indicates that there is no strong system size effect under a constant volume or a constant pressure. Both the mass distributions and the light particle multiplicities show a strong α clusterization at low excitation energies in the static AMD simulations. The liquid-gas phase transition measures of the multiplicity derivative (dM/dT) and the normalized variance of Z _max (NVZ) are applied. The experimental caloric curves are also compared with those of ¹⁰⁰Sn of the static AMD simulations under both the constant volume and the constant pressure conditions. Discussions are presented with the available experimental results and those from the static AMD simulations. Large errors in the experimental temperature measurements and those in the reconstruction technique for the primary fragmenting source hinder to draw a conclusion whether the phase transition occurs under either a constant volume or a constant pressure. This study suggests that different measures for the liquid-gas phase transitions should be examined besides the caloric curves in order to draw a conclusion.

在恒定体积或恒定压力下，在静态反对称分子动力学 (静态 AMD) 模型的框架内研究核液-气相变。应用氘核四极动量脉动温度计提取³⁶ Ar 和¹⁰⁰ Sn裂解系统的温度。对于密度为ρ ⩽ 0.03 fm ^{-3 的}那些系统，在恒定体积下观察到热量曲线的平台结构。在恒定压力下观察到热量曲线中明显的回弯，表明一级相变，并在所有研究压力下观察到。³⁶ Ar 和¹⁰⁰ Ar的热量曲线的相似行为Sn 系统表明在恒定体积或恒定压力下没有强烈的系统尺寸效应。在静态 AMD 模拟中，质量分布和轻粒子多重性都在低激发能下显示出强烈的α聚类。应用了多重导数 (d M /d T ) 和Z _max (NVZ)的归一化方差的液-气相变测量。实验热量曲线也与¹⁰⁰在恒定体积和恒定压力条件下静态 AMD 模拟的 Sn。讨论了可用的实验结果和静态 AMD 模拟的结果。实验温度测量和主要破碎源重建技术中的大误差阻碍了得出相变是在恒定体积还是恒定压力下发生的结论。这项研究表明，除了热量曲线外，还应检查液-气相变的不同措施，以便得出结论。