Vibrational Properties of Hydroperoxyl Radical-Water Clusters Using Quantum Algorithms for Wavepacket Dynamics.

We present the first quantum computing simulation of wavepacket dynamics in an HO₂-water cluster. These systems are of great interest in atmospheric chemistry and, due to anharmonicity, can display multidimensional quantum nuclear effects arising from delocalized hydrogen bond networks. Here, we utilize the Quantum Shannon Decomposition (QSD) method to represent a quantum propagator for the nuclear degrees of freedom of the HO₂ radical interacting with one and two water molecules, in the presence of an electronic potential energy surface, and in terms of the Ry, Rz, and CNOT quantum gates. The resultant time evolution of the quantum wavepacket, constructed by using the Qiskit quantum simulation tool, with a Python driver, yields a vibrational spectrum that is in very good agreement with the classically obtained result. The numerical demonstration here is restricted to one- and two-nuclear dimensions and hence is a proof of principle, but future implementations will include novel tensor network strategies to reduce quantum circuit depth and expand to higher dimensions.