  A lot of progress has been made in recent times for simulating accurately the
ground state energy of small molecules and their potential energy surface,
using quantum-classical hybrid computing architecture. While these single point
energy calculations are a significant milestone for quantum chemistry
simulation on quantum hardware, a similarly important application is to trace
accurately the reaction pathway of various chemical transformations. Such
computations require accurate determination of the equilibrium or lowest energy
molecular geometry, either by computing energy gradients with respect to the
molecule's nuclear coordinates or perturbative distortion of the molecular
configuration. In this work, we present a modular quantum-classical hybrid
framework, to accurately simulate chemical reaction pathway of various kinds of
molecular reactions. We demonstrate our framework by accurately tracing the
isomerization pathway for small organic molecules. This framework can now be
readily applied to study other 'active' molecules from the pharma and chemical
industries.
