Modified Intermediate Neglect of Differential Overlap MINDO

1 Modified Intermediate Neglect of Differential Overlap (MINDO) 

MrNDO/3 has been parameterized for H, B, C. N, O, F, Si, P. S and Cl. although certain combinations of these elements have been omitted. MINDO/3 is rarely used in modern computational chemistry, having been succeeded in accuracy by the NDDO methods below. Since there are parameters in MINDO which depend on two 

The MNDO, AMI and PM3 methodsare parameterizations of the NDDO model, where the parameterization is in terms of atomic variables, i.e. referring only to the nature of a single atom. MNDO, AMI and PM3 are derived from the same basic approximations (NDDO), and differ only in the way the core-core repulsion is treated, and how the parameters are assigned. Each method considers only the valence s- and p-fimctions, which are taken as Slater type orbitals with corresponding exponents, Ci and 

The two-center one-electron integrals given by the second equation in (3.74) are written as a product of the corresponding overlap integral times the average of two atomic resonance parameters, (5. 

Three versions of Modified Intermediate Neglect of Differential Overlap (MINDO) models exist, MINDO/1, MINDO/2 and MINDO/3. The first two attempts at parameterizing INDO gave quite poor results, but MINDO/3, introduced in 1975, produced the first general purpose quantum chemical method which could successfully 

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Modified intermediate neglect of differential overlap (MINDO/3) and modified neglect of differential overlap (MNDO) methods with full geometry optimization calculate triazol[4,5-, [l,2,3]triazole to possess antiaromatic structure with C h symmetry but not 1)2,5. In contrast, the aromatic structure with 1)2,5 symmetry is found advantageous for the 2,5-dioxide derivative <1991IZV1825>. 

A variety of more advanced, all-electron methods of this type Me available, and are generally referred to as semi-empirical calculations. The acronyms used to name the individual methods are descriptive of the manner in which atomic overlap calculations are performed. Among the more widely used semi-empirical methods are those of complete neglect of differential overlap (CNDO/2) (12), modified intermediate neglect of differential overlap (MINDO/3) (13), and modified neglect of diatomic overlap (MNDO) (14). 

According to a modified intermediate neglect of differential overlap (MINDO)/3 calculation, the highest occupied molecular orbital (HOMO) of a dicyanoDHI 7 shows a wave function similar to the lowest unoccupied molecular orbital (LUMO). Thus a locally excited (LE) transition (n-Jt ) is most probably hidden under this band. The assignment of a second band of 7 is less clear. 

Like their related methods such as the Intermediate Neglect of Differential Overlap (INDO) [2] and Modified Intermediate Neglect of Differential Overlap (MINDO) [6] the methods already mentioned have a number of features in common. They are all self-consistent field (SCF) methods that take into account electrostatic repulsion and exchange stabilization and where all integrals are evaluated by approximate means. They are further characterized by the fact that they all use a restricted basis set, that is, one s oibital and three p orbitals per atom, except for the hydrogen atom, which is represented by an s orbital. 

The INDO method may be further modified in parameterization of the spin effects as developed by Dewar s group and lead with the Modified Intermediate Neglect of Differential Overlap (MINDO) method (Pople and Beveridge 1970 Baird and Dewar 1969 Dewar and Hasselbach 1970 Dewar and Lo 1972 Bingham et al. 1975a, b, c, d Dewar et al. 1975 Murrell and Harget 1971) whose basic equations look like... 

Modified Intermediate Neglect of Differential Overlap (MINDO, MINDO/3) method, 84 Modified Neglect of Diatomic Overlap (MNDO) method, 86 Modified Neglect of Diatomic Overlap, Parametric Method Number 3 (MNIX)-PM3) method, 88... 

There are three modified intermediate neglect of differential overlap (MINDO) methods MINDO/1, MINDO/2, and MINDO/3. The MINDO/3 method is by far the most reliable of these. This method has yielded qualitative results for organic molecules. However its use today has been superseded by that of more accurate methods such as Austin model 1 (AMI) and parameterization method 3 (PM3). MINDO/3 is still sometimes used to obtain an initial guess for ab initio calculations. 

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