Ghost effect

Considering the different calculated values for an individual complex in Table 11, it seems appropriate to comment on the accuracy achievable within the Hartree-Fock approximation, with respect to both the limitations inherent in the theory itself and also to the expense one is willing to invest into basis sets. Clearly the Hartree-Fock-Roothaan expectation values have a uniquely defined meaning only as long as a complete set of basis functions is used. In practice, however, one is forced to truncate the expansion of the wave function at a point demanded by the computing facilities available. Some sources of error introduced thereby, namely ghost effects and the inaccurate description of ligand properties, have already been discussed in Chapter II. Here we concentrate on the... 

The refresh rate is the time required for the picture elements to change state (on or off). These times need not be the same. Typically, a pixel takes longer to go off than to go on. If the refresh time of a pixel is too long, ghosting effects will occur in rapidly changing images. 

There is no permanent spontaneous polarization, but polarization emerges when needed. Hence the switching may not be hampered by the so-called ghost effect or the unnecessarily strong, difficult to erase, memory effect. 

There are variations of this method. For example may it be argued that the full set of ghost orbitals should not be used, since some of the functions in the complex are used for describing the electrons of the other component, and only the virtual orbitals are available for artificial stabilization. However, it appears that the method of full counterpoise corection (using all basis functions as ghost orbitals) gives the best results. Note that A cp is an approximate correction, it gives an estimate of the BSSE effect, but it does not provide either an upper or lower limit. 

Note that the presence of modulation, or ghost peaks, is not an absolute indication of a problem within the machine-train. Couple effects may simply increase the amplitude of the fundamental mnning speed and do little damage to the machine-train. However, this increased amplitude will amplify any defects within the machine-train. 

In the early 1990s, Bakker and Van den Akker (1991, 1994) introduced an approximate but effective Euler Euler approach (see also A. Bakker s PhD Thesis, 1992) on the basis of a single-phase RANS flow field calculated by FLUENT, a code named GHOST calculated local and averaged values of bubble size db, gas hold-up a, and specific mass transfer rate kfl. 

If, in fact, the environment atoms are allowed to move, the rigorous estimation of A/.>7- is unclear. Kollman and co-workers have assumed that the effect of the ghost forces cancel for comparisons of similar ligands, and used a transition rule following Equation 18 instead of Equation 35 in their CMC/MD simulations.7,53 This approximation was demonstrated for some systems to be at least qualitatively reasonable.6,7... 

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