GCMC simulations canonical Monte Carlo

A grand-canonical Monte Carlo (GCMC) simulation for a one-component system is performed as follows. The simulation cell has a fixed volume V, and periodic... 

The grand canonical ensemble is appropriate for adsorption systems, in which the adsorbed phase is in equilibrium with the gas at some specified temperature. The use of a computer simulation allows us to calculate average macroscopic properties directly without having to explicitly calculate the partition function. The grand canonical Monte Carlo (GCMC) method as applied in this work has been described in detail earlier (55). The aspects involving binary fluid mixtures have been described previously in our Xe-Ar work (30). 

Since the preferential interaction coefficient T can be interpreted in terms of Donnan equilibrium [66, 74, 96, 97], a grand canonical Monte Carlo (GCMC) simulations could be used to determine it, from a knowledge of the slope of salt concentration c3 as a function of the polyion concentration cD [68, 73, 74]. Such an analysis was carried out by Olmsted and Hagerman for a tetrahedral four-arm DNA junction, based on the so-called primitive model of the electrolyte [74]. 

In this work, we explore the use of the pair correlation function as the target function in our reconstruction method [4]. This speeds up the simulations, allowing us to construct models in much larger simulation boxes. We build models for two saccharose-based carbons treated at different temperatures. We compare the exact pore size distributions and perform Grand Canonical Monte Carlo (GCMC) simulations of nitrogen at 77 K in the resulting models. 

In this paper, we present a model for activated carbon that takes into account the characteristics of the adsorbent that affect the adsorption of both polar and non-polar species. The structure of the carbon is represented by a PSD, obtained from the analysis of pure-ethane adsorption, and chemical heterogeneity is included by placing regularly distributed carbonyl sites on the surface of the pores. The single-pore isotherms for water and ethane are calculated by grand canonical Monte Carlo (GCMC) simulation. 

In this study, N2 adsorption in the internal pore of single SWNH particle and on external pores of bundled SWNH particles is simulated with grand canonical Monte Carlo (GCMC) method and the simulated isotherms are compared with the experimental results. 

The absolute adsorption isotherm as a function of gas-phase fuga ity is obtained directly from molecular simulations based on the grand canonical Monte Carlo (GCMC) method. Since the difference between absolute and excess adsorption is negligible at sub-atmospheric pressure, the low-pressure portion of the absolute isotherm can adso be determined from experiment. Eq. (2) is suitable for extrapolating the absolute isotherm from low to high pressure and Eq. (3) provides the conversion to excess adsorption. Experiments are needed to test these predictions of adsorption at high pressure. 

Up to now, numerous studies have been conducted on their synthesis [9,10], treatment [5,13] and physical properties [4], However only limited number of studies has been carried out on die adsorption of gas in CNTs, including experimental works [8,11] and molecular simulations [3,7,14-lS]. Adsorption behavior depends strongly on the microporous structure of the particular adsorbent. In this work the effect of pore size on the adsorption behavior is of interest. The adsorption equilibria of methane, ethane and their mixture into SWNTs were studied by using a Grand Canonical Monte Carlo (GCMC) method. We reported equilibrium isotherms of methane and ethane, and the selectivity from their equimolar mixture. 

In this paper we report, first, grand canonical Monte Carlo (GCMC) simulations of LJ fluid modeled on methane in slit-shaped nanopores that are kept equilibrium with saturated vapor, or pure liquid, in bulk phase. Depending on the strength of the attractive potential energy from pore walls, fluid in a pore shows freezing point elevation as well as depression. 

Figure 1 PSDs obtained using grand canonical Monte Carlo (GCMC) molectdar simulation to interpret CH4, CF4 and SFfi adsorption isotherms on activated carbon at 296 K [24].

Essential progress has been made recently in the area of molecular level modeling of capillary condensation. The methods of grand canonical Monte Carlo (GCMC) simulations [4], molecular dynamics (MD) [5], and density functional theory (DFT) [6] are capable of generating hysteresis loops for sorption of simple fluids in model pores. In our previous publications (see [7] and references therein), we have shown that the non-local density functional theory (NLDFT) with properly chosen parameters of fluid-fluid and fluid-solid intermolecular interactions quantitatively predicts desorption branches of hysteretic isotherms of nitrogen and argon on reference MCM-41 samples with pore channels narrower than 5 nm. 

In the work of Rowley et al. [1-3], the grand canonical Monte Carlo (gcmc) method was used to simulate Ar interacting with graphite. The surface was approximated as a continuum. In such a case, the sum in Eqn (4.3) is replaced by an integral in the x, y, and z dimensions (the graphite solid) and the potential reduces to a L-J 9-3 form that is a function only of the distance of the atom... 

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