Data classes

QDK/Chemistry uses immutable data classes to represent molecular information, electronic structure results, and quantum objects. These classes serve as the inputs and outputs for algorithm classes, enabling a clean flow of data through the computational pipeline. All data classes support serialization to JSON and HDF5 formats for persistence and interoperability.

Comprehensive details on each data class can be found in the API documentation. Here, we provide a quick reference guide to help users understand the purpose and typical sources of commonly encountered data classes. Each of the links below leads to a detailed description of the data class, including its attributes, methods, and usage examples.

Quick reference

Data Class	Purpose	Typical Source
Structure	Molecular geometry (atoms and coordinates)	User input
BasisSet	Atomic orbital basis definitions	Library lookup, User input
Orbitals	Molecular orbital coefficients and energies	ScfSolver
Hamiltonian	One- and two-electron integrals	HamiltonianConstructor
Wavefunction	Electronic state (orbitals + CI coefficients)	MCCalculator
QubitHamiltonian	Pauli operator representation	QubitMapper
PauliOperator	Pauli operator expressions with arithmetic	User construction

Contents

• Serialization
• BasisSet
• Hamiltonian
• Orbitals
• Pauli Operators
• Structure