Dreiding force-field

The heptane water and toluene water interfaces were simulated by the use of the DREIDING force field on the software of Cerius2 Dynamics and Minimizer modules (MSI, San Diego) [6]. The two-phase systems were constructed from 62 heptane molecules and 500 water molecules or 100 toluene molecules and 500 water molecules in a quadratic prism cell. Each bulk phase was optimized for 500 ps at 300 K under NET ensemble in advance. The periodic boundary conditions were applied along all three directions. The calculations of the two-phase system were run under NVT ensemble. The dimensions of the cells in the final calculations were 23.5 A x 22.6 Ax 52.4 A for the heptane-water system and 24.5 A x 24.3 A x 55.2 A for the toluene-water system. The timestep was 1 fs in all cases and the simulation almost reached equilibrium after 50 ps. The density vs. distance profile showed a clear interface with a thickness of ca. 10 A in both systems. The result in the heptane-water system is shown in Fig. 3. Interfacial adsorption of an extractant can be simulated by a similar procedure after the introduction of the extractant molecule at the position from where the dynamics will be started. 

As in the case of Tripos 5.252, several amino and nitro compounds were retrieved from the CSD and analyzed for their (all) atom movements upon energy minimization. Although the set of 19 amino and nitro compounds calculated with DREIDING is identical to that examined by Tripos 5.2, a direct comparison between the performance of the two force fields is not possible since the former reported RMS movements of all atoms while the latter, of heavy atoms only. The all atom average RMS movement reported by DREIDING for the set of 19 compounds is 0.298 A and the conclusions we derived for the Tripos force field apply also here. Additional results obtained with the DREIDING force field are discussed in Section II.D. 

BIOGRAF supports a number of force fields (AMBER, MM2, and DREIDING). The DREIDING force field, developed for the BIOGRAF... 

The same situation is expected for stereoisomers of the dendrimer 6 (G = 1), as revealed by a careful inspection of Figure 10 in which the dependence of the fractal dimension of the 12 isomers on probe radii is depicted. Due to the large number of atoms of this open-shell dendrimer, a low level theoretical method, the Dreiding force-field, was used for the optimizations of the geometries of these 12 isomers. ... 

The DREIDING force field is one of the newer force fields in this list, and was developed for the simulation of organic, biological, and main-group inorganic molecules [79]. 

Raman lines in nickel and copper porphyrins have been complemented by modified DREIDING force-field calculations [515-517]. 

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