  Quantum computing is of great potential for chemical system simulations. In
this study, we propose an efficient protocol of quantum computer based
simulation of chemical systems which enables accurate chemical reaction
modeling on noisy intermediate-scale quantum (NISQ) devices. In this protocol,
we combine an correlation energy-based active orbital selection, an effective
Hamiltonian from the driven similarity renormalization group (DSRG) method, and
a noise-resilient wavefunction ansatz. Such a combination gives a quantum
resource-efficient way to accurately simulate chemical systems. The power of
this protocol is demonstrated by numerical results for systems with up to tens
of atoms. Modeling of a Diels-Alder (DA) reaction is also performed on a
cloud-based superconducting quantum computer. These results represent an
important step forward in realizing quantum utility in the NISQ era.
