Homogeneous nucleation of nitrogen

Abstract

We investigated the homogeneous nucleation of nitrogen in a cryogenic expansion chamber [A. Fladerer and R. Strey, J. Chem. Phys. 124, 164710 (2006)]. Gas mixtures of nitrogen and helium as carrier gas were adiabatically expanded and cooled down from an initial temperature of 83 K until nucleation occurred. This onset was detected by constant angle light scattering at nitrogen vapor pressures of 1.3-14.2 kPa and temperatures of 42-54 K. An analytical fit function well describes the experimental onset pressures with an error of +/-15%. We estimate the size of the critical nucleus with the Gibbs-Thomson equation yielding critical sizes of about 50 molecules at the lowest and 70 molecules at the highest temperature. In addition, we estimate the nucleation rate and compare it with nucleation theories. The predictions of classical nucleation theory (CNT) are 9 to 19 orders of magnitude below the experimental results and show a stronger temperature dependence. The Reguera-Reiss theory [Phys. Rev. Lett. 93, 165701 (2004)] predicts the correct temperature dependence at low temperatures and decreases the absolute deviation to 7-13 orders of magnitude. We present an empirical correction function to CNT describing our experimental results. These correction parameters are remarkably close to the ones of argon [Iland et al., J. Chem. Phys. 127, 154506 (2007)] and even those of water [J. Wolk and R. Strey, J. Phys. Chem. B 105, 11683 (2001)].

A Review of Classical and Nonclassical Nucleation Theories

“…Experimental measurement of nucleation of argon is very difficult because of the difficulties associated with the maintenance of cryogenic temperatures. Discrepancies of 16–26 orders of magnitude and 11–13 orders of magnitude have been reported by two different groups. , Similarly for nitrogen, CNT underpredicts the rates by 9–19 orders of magnitude . Monte Carlo simulation studies reveal that the error in the calculation of work of cluster formation arises out of modeling the smallest clusters as liquid drops.…”

“…59,60 Similarly for nitrogen, CNT underpredicts the rates by 9−19 orders of magnitude. 61 Monte Carlo simulation studies reveal that the error in the calculation of work of cluster formation arises out of modeling the smallest clusters as liquid drops. Correction factors were needed to correct the work of cluster formation which results in the nucleation rates in good agreement with the experiments for argon and water.…”

Overview: Homogeneous nucleation from the vapor phase—The experimental science

“…Thus, it is possible to investigate binary systems that are immiscible in the liquid state. 128,[154][155][156] If growth is so fast that the recompression pulse cannot be shortened enough to decouple nucleation from growth, as is true of Ar nucleation studies, 52,53 running the NPC in free expansion mode is still informative. Such experiments yield S crit (T) as well as order of magnitude estimates for the nucleation rates, where the latter are based on the timescales and geometry of the experiment.…”

Development of an ultraviolet constant angle Mie scattering detector toward the determination of aerosol growth kinetics in the transition and free molecular regime

“…Pioneers include the work of (Sutugin and Fuchs 1968;1970) Reports exist on the usage of the constant angle Mie scattering (CAMS) method based on a fast expansion and recompression pulsed chamber to separate homogeneous nucleation from subsequent growth. In the experiment a He-Ne laser (k ¼ 632.8 nm) at 15 was utilized for water (Fladerer and Strey 2003) and cryogenic gases (Fladerer and Strey 2006;Iland et al 2009;Iland et al 2007). The system water in air using a HeNe red laser (k ¼ 632 nm) provided aerosol growth measurements in the continuum regime (Wagner 1985;Winkler et al 2004).…”