Mulliken charge distribution

In this form, it becomes possible to analyze the merits of Mulliken charge distributions in comparisons with physical observables. Namely, we want to learn the true value of n and the appropriate value of A for given choices of basis sets. Three approaches were followed to this end ... 

A few years later, Apeloig and Kami reported ab initio calculations of the structure, frontier molecular orbital energies and Mulliken charge distributions in a series of substituted silenes of structure RHSi=CH2 and H2Si=CHR, which indicated that all four of the substituents in the Brook silenes contribute to the reduction in Si=C bond polarity that was suggested to give rise to their unusual stability58. Their systematic study led to the conclusion that Si=C bond polarity is reduced by the presence of [Pg.995]

Fig. 6. Mulliken charge distribution where [Fe] and [P] stand for Cp(CO)Fe and P(NHCH2)2,...

In Chapter 1 we saw that in moving from homonuclear to heteronuclear diatomics a new factor enters - the atom characters are distributed differently over the filled and unfilled MOs. As only the filled orbitals contribute to the atomic charges, the Mulliken charge distribution reflects the polarity of the molecule. Similar information for the HOMO and FUMO permitted us to discuss properties such as Lewis acidity and basicity in terms of frontier-orbital characteristics. As we were able to unravel the DOS of the metal chain in terms of AO type, we can also interrogate the DOS of a heteroatomic system for information on the distribution of atomic character over the total DOS. That is, we can reveal the contributions or character of a chosen atom to the DOS. We can begin to appreciate the power of this tool by... 

TMS, and transfer of positive charge from R3Si+ to S in electrons derived from the Mulliken charge distribution. 

An investigation on the effects of the electrostatic force and the Mulliken charge distribution on the selectivity of MIPs was carried out based on DFT for hydroxyzine- and cetirizine-imprinted polymers [Azimi et al., 2014]. The results showed a correlation between the selectivity coefficients and the theoretical charge distributions and also showed that charge distribution based model was able to predict the selectivity coefficients of MIP based potentiometric sensors. 

In the case of a biomolecule, the bonds which fulfil the conditions to be frontier bonds are usually strongly covalent so that the Mulliken charge distribution can be performed. The Mulliken charge of the Y atom appears as the sum of three contributions the Y monocentric contributions, the Y-X... 

The calculated dipole moments are collected in Table 1 and drop when moving from ID to 2D structures. This decrease can be as large as 80 % of the initial value in some cases. The saturation of the dipole moment along the z-axis for a stack of three layers correlates well with the Mulliken charge distributions presented in Table 2. These charges are mostly confined within the interfacial layer when applying PBC in the plane while they are more delocalized for an isolated out-of-plane stack. 

For large molecules, computation time becomes a consideration. Orbital-based techniques, such as Mulliken, Lowdin, and NBO, take a negligible amount of CPU time relative to the time required to obtain the wave function. Techniques based on the charge distribution, such as AIM and ESP, require a sig-nihcant amount of CPU time. The GAPT method, which was not mentioned above, requires a second derivative evaluation, which can be prohibitively expensive. 

Despite these reservations, Mulliken population-derived atomic charges are easy to compute. Empirical investigation shows that they have various uses they provide approximate representation of the 3D charge distribution within a molecule. 

Charge Distributions. Mulliken population analyses have been used to calculate approximate charge distributions in a number of carbene complexes (see, for example, Refs. 10 and 12) and several conclusions can be drawn ... 

Charge. The small amount of charge distribution data for carbyne complexes (based on Mulliken population analyses) indicates that the metal-carbon bond is generally polarized Ms+—C5- and that the carbyne carbon is always more negative than adjacent carbonyl carbons (28,30). These conclusions are directly analogous to those derived for carbene complexes. 

Figure 17. Charge distribution of Cl2CH-C70+. Dots represent carbons possessing a Mulliken charge greater than 0.025 (B3LYP/6-31G ).

Figure 14.11 Charge distribution (A) (Mulliken charges) and spin distribution (B) in the intermediates BuC q and BuCjq. ...

The best estimate of 156.8 kl mol 1 for the activation energy is in reasonable agreement with the experimental value of 164 7 kJ mol 1 for the unsubstituted case. The Mulliken charges are consistent with the expected charge distribution shown in structure 462. The... 

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