Homogeneous nucleation and droplet growth in supersaturated argon vapor: the cryogenic nucleation pulse chamber.
Homogeneous nucleation and droplet growth in supersaturated argon vapor: the cryogenic nucleation pulse chamber.
复制标题
DOI：
10.1063/1.2186327
复制
发表时间：
2006-04
期刊：
影响因子：
--
通讯作者：
Alexander Fladerer;R. Strey
中科院分区：
文献类型：
--
作者：
Alexander Fladerer;R. Strey
我们建立了一个用于测量氩气均匀形核速率的低温形核脉冲室。首次测量表明，在成核条件下氩液滴的生长速率相当高，因此成核和生长还不能解耦。然而，实验允许估计成核的开始，其对应于在温度52<TK<59和大约10的S附近的过饱和下的J=10（7（+/-2））cm（-3）s（-1）的成核速率。尽管这些实验是初步的，但它们表明经典成核理论的严重失败，经典成核理论预测在所引用的条件下成核速率为10（-28）-10（-13）cm（-3）s（-1）。最近基于密度泛函理论的计算只能部分解释这种差异。除了第一个成核实验，我们获得和分析的氩液滴的生长曲线，从恒定角米氏光散射。实验生长曲线与根据Fuchs和Sutugin [高度分散的气溶胶（安阿伯科学，安阿伯，MI，1970）]的模型计算的良好一致性允许对实验光散射信号进行接近定量的描述。该程序提供了对液滴的数量密度的估计，沿着测量它们的多分散性。
We built a cryogenic nucleation pulse chamber for measuring homogeneous nucleation rates of argon. First measurements show that the growth rate of argon droplets at nucleation conditions is rather high so that nucleation and growth could not yet be decoupled. Nevertheless, the experiments permit an estimate of the onset of nucleation corresponding to a nucleation rate of J=10(7(+/-2)) cm(-3) s(-1) at temperatures 52<TK<59 and supersaturations around S approximately 10. Despite their preliminary nature these experiments indicate a severe failure of the classical nucleation theory, which predicts nucleation rates on the order of 10(-28)-10(-13) cm(-3) s(-1) for the quoted conditions. Recent calculations based on density functional theory can only partially explain the discrepancy. In addition to the first nucleation experiments, we obtained and analyzed growth curves for argon droplets from constant angle Mie-light scattering. The good agreement of the experimental growth curves with model calculations according to Fuchs and Sutugin [Highly Dispersed Aerosols (Ann Arbor Science, Ann Arbor, MI, 1970)] permits a near-quantitative description of the experimental light-scattering signal. The procedure provides an estimate for the number density of the droplets along with a measure of their polydispersity.