Modified neglect of differential overlap MNDO

The modified neglect of differential overlap (MNDO) model should probably come next MNDO is like INDO except that MNDO treats the diatomic two-electron integrals more accurately. It retains all two-electron integrals involving monatomic differential overlap, and the paper to read is probably ... 

In a seminal theoretical paper, we showed that, at the Modified Neglect of Differential Overlap (MNDO) level, phenylnitrenium ions 17 as well as NH2, PH2,... 

The bicyclo[2.2.2]octane-l,4-diyl dication, 61, and its tricyclopropane derivative, 62, could not be prepared under stable ion conditions even though they were attempted under various reaction conditions. The possible existence of these carbodications was supported by Modified Neglect of Differential Overlap (MNDO) calculations. 

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>. 

Dewar and Thiel (1977) reported a modified neglect of differential overlap (MNDO) method based on the NDDO formalism for the elements C, H, O, and N. With the conventions specified by NDDO for which integrals to keep, which to discard, and how to model one-electron integrals, it is possible to write the NDDO Fock matrix elements individually for... 

Dewar and coworkers parameterized these approaches to give the modified intermediate neglect of differential overlap/3 (MINDO/3) <1975JA1285> and modified neglect of differential overlap (MNDO) <1977JA4899> methods. 

UV-PES studies of 1,2,4,6-thiatriazinyl [R2C2N3S] and 1,2,3,5-dithidiazolyl [RCN2S2] (15) radicals have also provided ionization potentials that are in good agreement with modified neglect of differential overlap (MNDO) calculations. " ... 

Ever since the introduction of the semi-empirical Extent Huckel Theoiy (EHT) by Hoffman [1] in the early 1960s and followed by the Complete Neglect of Differential Overlap (CNDO) method [2], there has been a constant evolution in the field of semi-empirical MO methods. This research has evolved into a situation where at present the computational chemist using the recent Modified Neglect of Differential Overlap (MNDO) [3] version and its more elaborate successors Austin Model (AMI) [4] and Parametrized Model (PM) [5] has a number of impressive tools at his or her disposal to describe the molecular structme and properties of molecules containing several hundreds of atoms. 

Further approximations of the Hiickel method were removed with the introduction of the complete neglect of differential overlap (CNDO) method, which is a slightly more sophisticated method for dealing with the terms H,k that appear in the secular equations for the coefficients. The introduction of CNDO opened the door to an avalanche of similar but improved methods and their accompanying acronyms, such as intermediate neglect of differential overlap (INDO), modified neglect of differential overlap (MNDO), and the Austin Model 1 (AMI, version 2 of MINDO). Software for all these procedures is now readily available, and reasonably sophisticated calculations can be run even on handheld computers. 

Several quantum-chemical methods with varying degrees of sophistication are used in our theoretical investigations. We usually optimize the geometry of ohgothiophenes by means of the Hartree-Fock semiempirical Austin Model 1 (AMI) [41] or Modified Neglect of Differential Overlap (MNDO) [42] methods, that allow one to deal... 

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