ZINDO is a

semi-empirical quantum chemistry method Semi-empirical quantum chemistry methods are based on the Hartree–Fock formalism, but make many approximations and obtain some parameters from empirical data. They are very important in computational chemistry for treating large molecules where ...

used in computational chemistry. It is a development of the

INDO Indo may refer to: * Indo-, a prefix indicating India or the Indian Subcontinent * Indonesia, a country in Asia ** INDO LINES, callsign of Indonesian Airlines ** Indo people, people of mixed European and Indonesian ancestry ** Indo cuisine, fusion ...

method. It stands for Zerner's Intermediate Neglect of Differential Overlap, as it was developed by

Michael Zerner Michael Charles Zerner (January 1, 1940 – February 2, 2000) was an Americans, American theoretical chemist, professor at the University of Guelph from 1970 to 1981 and University of Florida from 1981 to 2000. Zerner earned his Ph.D. under Ma ...

and his coworkers in the 1970s. Unlike

, which was really restricted to organic molecules and those containing the atoms B to F, ZINDO covers a wide range of the periodic table, even including the

rare-earth element The rare-earth elements (REE), also called the rare-earth metals or (in context) rare-earth oxides or sometimes the lanthanides ( yttrium and scandium are usually included as rare earths), are a set of 17 nearly-indistinguishable lustrous silv ...

s. There are two distinct versions of the method: * ZINDO/1 – for calculating ground-state properties such as bond lengths and bond angles. It refers to a SCF (RHF or ROHF) calculation with the INDO/1 level as suggested by Pople, which provides the reference state MO coefficients. Ground-state dipole moments and ionization potentials are in general very accurate. Geometry optimizations are erratic, what prompted Zerner's group to improve the performance of the code in the late 1990sJ. D. Da Motta Neto, M. Zerner, Int. J. Quantum Chem. 2001, ''81'', 187–201. * ZINDO/S (sometimes just called INDO/S) – use the INDO/1

molecular orbital In chemistry, a molecular orbital is a mathematical function describing the location and wave-like behavior of an electron in a molecule. This function can be used to calculate chemical and physical properties such as the probability of findin ...

s for calculating excited states and hence electronic spectra. It consists of a CI calculation including only the reference state plus a small set of single-electron excitations within a selected active space, typically five HOMOs and five LUMOs. The original BIGSPEC program from the Zerner group is not widely available, but the method is implemented in

ORCA The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus '' Orcinus'' and is recognizable by its black-and-white ...

, in part, in

Gaussian Carl Friedrich Gauss (1777–1855) is the eponym of all of the topics listed below. There are over 100 topics all named after this German mathematician and scientist, all in the fields of mathematics, physics, and astronomy. The English eponymo ...

, and in

SCIGRESS Scigress, stylized SCiGRESS, is a software suite for molecular modelling, computational chemistry, drug design, and materials science, a successor to ''Computer Aided Chemistry'' (CAChe) software. About Scigress is a molecular modeling suite ...

. To obtain good results, it is frequently necessary to fit the parameters to a given molecule, thereby making it ideal only in semi-empirical calculations.

References

Semiempirical quantum chemistry methods {{quantum-chemistry-stub