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Apparent interaction energy

A further paper [167] explains the lamellar thickness selection in the row model. The minimum thickness lmin is derived from the similation and found to be consistent with equilibrium results. The thickness deviation 81 = l — lmin is approximately constant with /. It is established that the model fulfills the criteria of a kinetic theory Firstly, a driving force term (proportional to 81) and a barrier term (proportional to /) are indentified. Secondly, the competition between the two terms leads to a maximum in growth rate (see Fig. 2.4) which is located at the average thickness l obtained by simulation. Further, the role of fluctuations becomes apparent when the dependence on the interaction energy e is investigated. Whereas downwards (i.e. decreasing l) fluctuations are approximately independent... [Pg.300]

The electrical double layer at Hg, Tl(Ga), In(Ga), and Ga/aliphatic alcohol (MeOH, EtOH) interfaces has been studied by impedance and streaming electrode methods.360,361 In both solvents the value ofis, was independent of cei (0.01 < cucio4 <0.25 M)and v. The Parsons-Zobel plots were linear, with /pz very close to unity. The differential capacity at metal nature, but at a = 0,C,-rises in the order Tl(Ga) < In(Ga) < Ga. Thus, as for other solvents,120 343 the interaction energy of MeOH and EtOH molecules with the surface increases in the given order of metals. The distance of closest approach of solvent molecules and other fundamental characteristics of Ga, In(Ga), Tl(Ga)/MeOH interfaces have been obtained by Emets etal.m... [Pg.67]

Since the interaction of linear hydrocarbons is dominated by the van der Waals interaction with the zeohte, the apparent activation energies for cracking decrease hnearly with chain length. In some cases, differences in the overall rate are not dominated by differences in the heat of adsorption but instead are dominated by differences in the enthrones of adsorbed molecules. [Pg.18]

This study presents kinetic data obtained with a microreactor set-up both at atmospheric pressure and at high pressures up to 50 bar as a function of temperature and of the partial pressures from which power-law expressions and apparent activation energies are derived. An additional microreactor set-up equipped with a calibrated mass spectrometer was used for the isotopic exchange reaction (DER) N2 + N2 = 2 N2 and the transient kinetic experiments. The transient experiments comprised the temperature-programmed desorption (TPD) of N2 and H2. Furthermore, the interaction of N2 with Ru surfaces was monitored by means of temperature-programmed adsorption (TPA) using a dilute mixture of N2 in He. The kinetic data set is intended to serve as basis for a detailed microkinetic analysis of NH3 synthesis kinetics [10] following the concepts by Dumesic et al. [11]. [Pg.318]

As is apparent from the above definitions, each of these effective matrices depend on basis sets and molecular orbitals of both fragments. It is also important to observe that these matrices possess a correct asymptotic behavior as at large interfragment distances they become the usual overlap and Fock matrices of the separate fragments, while the paired secular systems uncouple and converge to the separate Roothaan equations for the single monomers. Finally, as it is usual in a supermolecular approach, the interaction energy is expressed as... [Pg.107]

Most of these examples show that it is apparently easier to grow ordered arrays of more reactive metals, for example, Pd, than unreactive metals such as Au and Ag. This is most likely due to the low interaction energy of the latter metals with the oxide surfaces and, consequently, a lower specificity of the traps. This calls for a modification of the template to increase the interaction energy of the template sites (traps) with the deposited metals. [Pg.50]

Rotators in the solid state experience a well defined potential, with a depth and symmetry resulting from interactions with surrounding ions or molecules. Combined translation and rotation of CD4 lead to a much less specified meaning of the apparent activation energy obtained experimentally. Obtained values indicate that we have different values of the activation energy for different temperature ranges. Therefore their relation to local potentials at the walls of cages requires a further study. [Pg.172]

We return to the complex formation equilibria described in Chapter 2 (Eqs. 2.1 -2.10). The equilibrium constants as given in these equations are essentially intrinsic constants valid for a (hypothetically) uncharged surface. In many cases we can use these constants as apparent constants (in a similar way as non-activity corrected constants are being used) to illustrate some of the principal features of the interdependent variables that affect adsorption. Although it is impossible to separate the chemical and electrical contribution to the total energy of interaction with a surface without making non-thermodynamic assumptions, it is useful to operationally break down the interaction energy into a chemical and a Coulombic part ... [Pg.67]

On the other hand, the estimate of the Breit interaction energy is, in all cases, quite satisfactory in any atomic or ionic superposition model. The reason for this has already been discussed the Breit interaction energy arises due to electron current density in the neighbourhood of the nuclei, which is dominated by the core electrons and is apparently insensitive to the valence electron environment. [Pg.135]

As sensitization has come into widespread use, it has become apparent that energy transfer is by no means the only process which can occur when a sensitizer is irradiated in the presence of an acceptor. Other unwanted and often totally unexpected interactions between the sensitizer and itself, the substrate, or the solvent can produce confusing or misleading results. These interactions, which include chemical reaction of sensitizers, involvement of singlet excited states, and numerous other complications, will constitute the... [Pg.246]

The fragmentation process depends on how much electrical energy (RF power) is supplied to maintain the plasma, how much monomer is introduced into the plasma, and where the monomer molecules interact with activated species of the plasma. Yasuda proposed a controlling parameter or W/FM value, where W, F, and M are RF power [J/s], the monomer flow rate [mol/s], and the molecular weight of the monomer [kg/mol], respectively [21]. The W/FM parameter is an apparent input energy per unit of monomer molecules [J/kg] therefore, the magnitude of the W/FM parameter is considered to be proportional to the concentration of activated species in the plasma. The polymer formation rate (polymer deposition rate) increases by increasing the W/FM parameter in the operational condition, whereby... [Pg.175]


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