Quantum-Centric Study of Methylene Singlet and Triplet States

Understand

This study explores the electronic structure of the CH$_2$ molecule, modeled as a (6e, 23o) system using a 52-qubit quantum experiment, which is relevant for interstellar and combustion chemistry.

• We focused on calculating the dissociation energies for CH$_2$ in the ground state triplet and the first excited state singlet, applying the Sample-based Quantum Diagonalization (SQD) method within a quantum-centric supercomputing framework.
• We evaluated the ability of SQD to provide accurate results compared to Selected Configuration Interaction (SCI) calculations and experimental values for the singlet-triplet gap.
• To our knowledge, this is the first study of an open-shell system, such as the CH$_2$ triplet, using SQD.