INDEX force-field parameters

Foldy-Wouthuysen transformation, 215 Forbidden reaction, Woodward-Hoffmaim rules, 356 Force Field (FF), 6 Force field energy, 8 Force field parameters, 30 Four index transformation of two-electron integrals, 105... 

It remains to find out whether a similar treatment can be developed for the torsion force fields habitually indexed by quadruples of atomic types and thus posing most problems in the prescription of parametrization. One can also think about following problem setting, namely of designing a set of MINDO/3 or NDDO parameters selected for using with the formulae of either of the approximations of the DMM family. In this case, the entire parameter set can be indexed by the only atomic types as no parameters indexed by pairs and even more by triples or quadruples of atomic types are previewed in a semiempirical setting. 

The main shortcoming, reported by Anderson [12] for the Amott methods, is their insensitivity near neutral wettability. In addition, the RDI relates relative volnmes of imbibition, but one also needs to look at these individual volumes to obtain a better understanding of flnid displacement as represented by this index. More recently, Ma [15] reported that the Amott test also does not discriminate adequately at strongly water-wet conditions and proposed an imbibition rate method for wettability (see below). Other shortcomings include variations in laboratory procednres. The temperatnre and length of time employed for the spontaneons imbibition and the pressure used during the forced displacement cycle are often modified to match specific field parameters or for ease of measurement in the laboratory. Consequently, the qnantitative values that are obtained can differ from one laboratory to another for reasons that are not related just to the wettability of the rock sample. 

The nematic liquid crystal is orientationally soft, since restoring forces associated with deformation in the director field are very weak. This softness makes alignment of n in bulk samples occur even in very weak external magnetic or electric fields, F s H or E, or by interaction with boundary surfaces and flows in the liquid. This softness also allows for long wavelength thermal fluctuations in the director field. The Leslie viscosity parameters rather than the viscosity coefficients are the more natural quantities of interest for those methods that monitor the viscoelastic response of the nematic to director field modulations. Modulation of n in space and time manifests itself in variations of many bulk properties, e.g. the refractive index [27-37,41-44,48,51,94-106], electric susceptibility [38,39,107-110], or magnetic resonance spectra [40,45-47,111-113]. However, only a limited number of the viscosity parameters/coefficients can be precisely determined by these methods. 

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