Coordinates, atomic external

Fig. 3 Chemical shifts of " Cd for structurally characterized Cd-substituted metalloproteins relative to external 0.1 M [Cd(C104)]. The chemical shift positions are represented by gray bars and coordinating atoms are highlighted in blue with typical proteins listed besides. Here S represents sulfur from cysteine, S represents sulfur from methionine, O represents oxygen from carboxylate or water, and N represents nitrogen Ifom histidine [71]...

In summary, zinc is most suited to participate in formation of the sulfurating complex. Coordination of external ligands (ROO—,R 2NH ) of the zinc atom causes the bonding between XS—Sjc... and. .. Sy—SX groups to weaken, thereby increasing the contribution of the polar canonical form ... 

The different internal and external file formats make it necessary to have programs which convert one format into another. One of the first conversion programs for chemical structure information was Babel (around 1992). It supports almost 50 data formats for input and output of chemical structure information [61]. CLIFF is another file format converter based on the CACTVS technology and which supports nearly the same number of file formats [29]. In contrast to Babel, the program is more comprehensive it is able to convert chemical reaction information, and can calculate missing atom coordinates [29]. 

However, it is common practice to sample an isothermal isobaric ensemble NPT, constant pressure and constant temperature), which normally reflects standard laboratory conditions well. Similarly to temperature control, the system is coupled to an external bath with the desired target pressure Pq. By rescaling the dimensions of the periodic box and the atomic coordinates by the factor // at each integration step At according to Eq. (46), the volume of the box and the forces of the solvent molecules acting on the box walls are adjusted. 

Based on detailed kinetic investigations, a tentative mechanism for this asymmetric oxidation was proposed (Scheme 2) according to which optically active sulphoxides may be formed by two pathways external attack on the sulphur atom by the chiral titanium hydroperoxide (path A) or coordination of sulphur to titanium prior to the oxidation step (path B). Although paths A and B could not be distinguished experimentally, the temperature effect was tentatively ascribed to a change of the mechanism, path A being predominant above — 20 °C and path B becoming competitive at lower temperatures (or vice versa). 

The Hamiltonian operator for a hydrogen atom in a uniform external electric field E along the z-coordinate axis is... 

We consider a molecule with Q nuclei, each with atomic number Z and mass Ma (a = 1, 2,. .., Q), and N electrons, each of mass Wg. We denote by Q the set of all nuclear coordinates and by r the set of all electronic coordinates. The positions of the nuclei and electrons are specified relative to an external set of coordinate axes which are fixed in space. 

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