NDDO stands for neglect of diatomic differential overlap. The formalism was first introduced by John Pople

John Pople

Sir John Anthony Pople, KBE, FRS, was a Nobel-Prize winning theoretical chemist. Born in Burnham-on-Sea, Somerset, England, he attended Bristol Grammar School. He won a scholarship to Trinity College, Cambridge in 1943. He received his B. A. in 1946. Between 1945 and 1947 he worked at the Bristol...

 and it is now the basis of most successful semiempirical methods. While INDO

INDO

INDO stands for Intermediate Neglect of Differential Overlap. It is a semi-empirical quantum chemistry method that is a development of the complete neglect of differential overlap method introduced by John Pople...

 added all one-centre two electron integrals to the CNDO/2

CNDO/2

CNDO is the abbreviation for Complete Neglect of Differential Overlap. Although CNDO is based on quantum chemistry, it is more specifically one of the first semi-empirical quantum chemistry methods. It uses two approximations:...

 formalism, NDDO adds all two centre integrals for repulsion between a charge distribution on one centre and a charge distribution on another centre. Otherwise the zero-differential overlap

Zero-differential overlap

Zero differential overlap is an approximation that is used to ignore certain integrals, usually two-electron repulsion integrals, in semi-empirical quantum chemistry methods quantum chemistry molecular orbital methods....

 approximation is used.

A common software program is MOPAC (Molecular Orbital PACkage).

See also

• MNDO
  MNDO
  MNDO, or Modified Neglect of Differential Overlap is a semi-empirical method for the quantum calculation of molecular electronic structure in computational chemistry. It is based on the Neglect of Differential Diatomic Overlap integral approximation. Similarly, this method replaced the earlier...
  
  
• AM1
• PM3
  PM3 (chemistry)
  PM3, or Parameterized Model number 3, is a semi-empirical method for the quantum calculation of molecular electronic structure in computational chemistry. It is based on the Neglect of Differential Diatomic Overlap integral approximation....
  
  
• SAM1
  SAM1
  SAM1, or "Semiempirical ab initio Model 1", is a semiempirical quantum chemistry method for computing molecular properties. It is an implementation the general Neglect of Differential Diatomic Overlap integral approximation, and is efficient and accurate. Related methods are AM1, PM3 and the older...
  
  
• RM1
• MOPAC
  MOPAC
  In computational chemistry, MOPAC is a popular computer program designed to implement semi-empirical quantum chemistry algorithms, such as MINDO, MNDO, AM1, PM3, PM5, and . It was largely written in the group of Michael Dewar at University of Texas, Austin...