MNDO modified neglect of diatomic

MNDO (modified neglect of diatomic overlap) a semiempirical method model a simple way of describing something that is actually more complex than the model... 

Calculations by the MNDO (modified neglect of diatomic overlap) method with full optimization of geometry were carried out for [Zn, N, C, H]+ ions indicating the possible existence of four stable isomers (Figure 7). According to the same semi-empirical method, [Zn, N, C2, H3]+ ions can form nine stable isomeric stmctnres (Fignre 7) In a separate study by density functional theory, self-assembled helicate architectures have been proposed for ions of the [Zn (CN)2 +i] series. ... 

MNDO Modified Neglect of Diatomic Differential Overlap... 

Compounds containing silicon bonded to only one other atom are unstable and are usually only generated and observed as reactive intermediates of short half-life. Silicon compounds subjected to flash photolysis or electrical discharges in the gas phase produce short-lived species SiX (X = H, F, Cl, Br, I, C, Si, etc.), the band structure of which have been studied in detail. The structures, electronic configurations, and so on of Six (X = H, F, Cl, Br, I, N, O, etc.) have also been the subject of MNDO (modified neglect of diatomic overlap) and other calculations. ... 

This method is valid only in the static field limit (zero frequency), which is a weakness. However, recent advances of a derived procedure (Coupled Perturbed Hartree-Fock) permit the frequency dependence of hyperpolarizabilities to be computed. The FF method mainly uses MNDO (modified neglect of diatomic differential overlap) semi-empirical algorithm and the associated parametrizations of AM-1 and PM-3, which are readily available in the popular MOPAC software package. ... 

MNDO Modified-neglect-of-diatomic overlay (method)... 

As an alternative to ab initio methods, the semi-empirical quantum-chemical methods are fast and applicable for the calculation of molecular descriptors of long series of structurally complex and large molecules. Most of these methods have been developed within the mathematical framework of the molecular orbital theory (SCF MO), but use a number of simplifications and approximations in the computational procedure that reduce dramatically the computer time [6]. The most popular semi-empirical methods are Austin Model 1 (AMI) [7] and Parametric Model 3 (PM3) [8]. The results produced by different semi-empirical methods are generally not comparable, but they often do reproduce similar trends. For example, the electronic net charges calculated by the AMI, MNDO (modified neglect of diatomic overlap), and INDO (intermediate neglect of diatomic overlap) methods were found to be quite different in their absolute values, but were consistent in their trends. Intermediate between the ab initio and semi-empirical methods in terms of the demand in computational resources are algorithms based on density functional theory (DFT) [9]. 

MNDO modified neglect of diatomic overlap MS mass spectrum... 

More recently gas-phase nitration was treated theoretically with MNDO (modified neglect of diatomic differential overlap) and INDO (intermediate neglect of differential overlap) self-consistent field calculations (34). Electron transfer and radical-pair recombination were favored for the nitration of toluene and the xylenes but not for nitrobenzene, for which a classical nitration route via a tt complex was favored. The calculations could not make a distinction between the two routes in the nitration of benzene. More information is needed about these coupling reactions and how they differ in the gas and heterogeneous-solution phases. 

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