  Currently available noisy intermediate-scale quantum (NISQ) devices are
limited by the number of qubits that can be used for quantum chemistry
calculations on molecules. We show herein that the number of qubits required
for simulations on a quantum computer can be reduced by limiting the number of
orbitals in the active space. Thus, we have utilized ans\"atze that approximate
exact classical matrix eigenvalue decomposition methods (Full Configuration
Interaction). Such methods are appropriate for computations with the
Variational Quantum Eigensolver algorithm to perform computational
investigations on the rearrangement of the lithium superoxide dimer with both
quantum simulators and quantum devices. These results demonstrate that, even
with a limited orbital active space, quantum simulators are capable of
obtaining energy values that are similar to the exact ones. However,
calculations on quantum hardware underestimate energies even after the
application of readout error mitigation.
