What is zmat?

Z-Matrix (also known as Z-Matrix Notation or Internal Coordinate System) is a type of molecular modeling technique used in the field of computational chemistry to represent the position of atoms in a molecule. It is a mathematical representation that uses the distance between two atoms, the angle between three atoms, and the dihedral angle between four atoms to describe the three-dimensional structure of a molecule.

The Z-matrix notation is used in several molecular modeling software programs and is useful for predicting the structures of complex and large molecules. It simplifies the calculation of the potential energy of a molecule and allows for easy optimization of the geometry of the molecule.

The Z-matrix notation includes the atomic coordinates of each atom in the molecular structure, along with the distance, angle, and dihedral angle values. The notation allows for easy modification of the molecular structure by changing the values of the angles and dihedral angles, which can be used to study the changes in the molecular geometry and conformational changes in a molecule.