ZINDO is a
semi-empirical quantum chemistry method used in
computational chemistry
Computational chemistry is a branch of chemistry that uses computer simulations to assist in solving chemical problems. It uses methods of theoretical chemistry incorporated into computer programs to calculate the structures and properties of mol ...
. It is a development of the
INDO method. It stands for Zerner's Intermediate Neglect of Differential Overlap, as it was developed by
Michael Zerner and his coworkers in the 1970s. Unlike
INDO, which was really restricted to organic molecules and those containing the atoms
B to
F, ZINDO covers a wide range of the
periodic table
The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows (" periods") and columns (" groups"). It is an icon of chemistry and is widely used in physics and other s ...
, even including the
rare-earth elements. 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 1990s
[J. 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 orbitals 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, in part, in
Gaussian, and in
SCIGRESS.
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