Neglect of differential overlap methods

There is one semiempirical program, called HyperNMR, that computes NMR chemical shifts. This program goes one step further than other semiempiricals by defining different parameters for the various hybridizations, such as sp carbon vs. sp carbon. This method is called the typed neglect of differential overlap method (TNDO/1 and TNDO/2). As with any semiempirical method, the results are better for species with functional groups similar to those in the set of molecules used to parameterize the method. 

To confirm equation (4), we used the FPT (Finite Perturbation Theory) INDO (Intermediate Neglect of Differential Overlap) method (39) to calculate the Jqjj for various values of torsion angles. A comparison of the experimental and calculated values is plotted in Figure 5. 

One semiempirical method which has been a workhorse in studies of fullerenes is the MNDO (Modified Neglect of Differential Overlap) method [4], which treats all valence electrons explicitly but within an essentially molecular... 

Table 5.18. Calculated and experimental geometries in borate polyhedra. Bond lengths and bond angles for the borate clusters shown calculated using ab initio SCF Hartree-Fock-Roothaan methods with various basis sets, and the modified electron-gas and modified neglect of differential overlap method, and compared with experimental values (see text for data sources)...

The Complete Neglect of Differential Overlap method (CNDO) ofPople et al. [8,37-39] makes use of the ZDO approximation [Eq. (26)] for all pairs of atomic basis functions. It treats explicitly all valence electrons (e.g., C 2s, C 2p), but neglects completely the... 

The earliest complete neglect of differential overlap method was introduced by Pople and his collaborators in 1965. - This scheme w as parameterized directly on minimum basis set ab initio calculations. ... 

Nitrogen-14 nuclear quadrupole coupling constants in oxazole have been calculated by using the complete neglect of differential overlap method (CNDO/2) including all the valence electrons,232 and from ab initio molecular-orbital wave functions using Gaussian basis sets.234... 

Ultraviolet Spectra. A comparison of UV spectra for phthalazines and related systems has been prepared and discussed in a comparative way. " The electronic spectra for phthalazine and other azanaphthalenes have been calculated by a modified INDO (intermediate neglect of differential overlap) method. ... 

According to quantum-chemical calculations, the metal-H20 interaction has been proposed to be in the sequence Hg < Ag(lOO) < In < Cu(lOO) [81]. Compared to the experimental data, it appears that the positions of In and Ag(lOO) are exchanged. The complete neglect of differential overlap method predicts for any given metal a weaker interaction on the more dense surface [40]. Thus, the predicted sequence is (111) < (100) < (110) for fee metals and (0001) < (1100) for hep metals. However, for the most compact surfaces, the calculated sequence is Hg < Ag(lll) < Cu(lll) Zn(OOOl) < Au(lll) < Cd(0001).Itisdifficult to accept that Zn can be less hydrophilic than Au or Cd, and also that Au can be more reactive than Cu. More recent calculations gave the other order of metals Ag < Au < Cu. This confirms the position of Cu, but Au still appears to be more reactive than Ag [5]. 

INDO intermediate neglect of differential overlap method... 

Hamiltonian is not known and, as for the nonrelativistic case, further approximations have to be introduced in the wavefunction, it is tempting to derive approximate computational schemes which are still sufficiently accurate but more efficient. Here we will only summarize those approximate methods that have been used frequently to obtain information about the electronic structure of molecules with lanthanide atoms, i.e. relativistically corrected density-functional approach, pseudopotential method, intermediate neglect of differential overlap method, extended Huckel theory, and ligand field theory. 

Andrade et al. (1994) developed a so-called sparkle model for Eu + ions in quantum-chemical calculations using the semiempirical Austin Model 1 (AMI) method (Dewar et al. 1985). In comparison to the related modified neglect of differential overlap method (MNDO) (Dewar and Thiel 1977a,b) the AMI method uses a modified core-core repulsion function and is therefore able to reproduce hydrogen bonds. The sparkle model is based on the a priori assumption that the interaction of the metal ion with... 

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