Average adsorption energies

This model is directly derived from the Langmuir isotherm. It assumes that the adsorbent surface consists of two different types of independent adsorption sites. Under this assumption, the adsorption energy distribution can be modeled by a bimodal discrete probability density function, where two spikes (delta-Dirac functions) are located at the average adsorption energy of the two kinds of sites, respectively. The equation of the Bilangmuir isotherm is... 

The value of eTO, the average adsorptive energy from the adsorbent hetero-... 

Table 12-2. The calculated optimal distribution of H2 and the average adsorption energy (kcal/mol) per H2. The statistical uncertainty of die averaged adsorption energy is approximately 0.5 kcal/mol...

Figure 10. Hydrogen adsorption in one- (a), four- (b), six- (c), and eight- (c) Sc-Cp-grafted structures. E is the average adsorption energy, rl is the average hydrogen molecule bond length, and r2 is the average distance between Hi and Sc.

Figure 6.2 (a) Values of surface fractal dimensions D, obtained from N2 adsorption data from the authors (diamonds), from [30] (circles), and from [95] (stars), (b) Average adsorption energies of water vapor (data from [96]) on various monoionic forms of montmorillonite as a function of the cation charge Z. Reproduced by permission of the Polish Academy of Sciences. 

It is noted that while eqs. (26) and (27) give the adsorption energy in each particular configuration (irrespective of the value of N), eq. (28) gives the dependence of the average adsorption energy on the adsorbed amoimt. 

To calculate the (average) adsorption energies of O2. tho following expression was considered ... 

Figure 1,7F refers to the case of coadsorption of two O2 molecules, and the number in parentheses corresponds to the average adsorption energy per O2 molecule. 

If there are surface sites on a clean surface and we adsorb N adsorbates on that surface, we define the fractional coverage as 6=N/N. hi terms of this coverage, the average adsorption energy is defined as... 

Table 2.1 Characterization of each stable adsorption site for 0-Pt(321) system A avg is the average adsorption energy, AEf is the formation energy, and is the zero-point vibrational energy.

Table 2.1 reports average adsorption energies for each of the 10 O adsorption sites on Pt(321) in order of inereasing average adsorption energy, calculated in a 2x2 supercell with one adsorbate per supereell (Na = 1) to simulate isolated adsorbates. Atomic energies eannot be aeeurately evaluated within the... 

Having calculated the DFT energy of a number of adsorbate eonfigurations at different coverages and on different supercells, we calculated the average adsorption energy for each configuration, and these are plotted as a funetion of... 

Figure 2.5 Plots of (left) average adsorption energy vs. coverage and (right) formation energy vi. coverage of several configurations of O on a 1 x 1 Pt(321) supercell.

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