  Simulating chemical systems is highly sought after and computationally
challenging, as the simulation cost exponentially increases with the system
size. Quantum computers have been proposed as a computational means to overcome
this bottleneck. Most efforts recently have been spent on determining the
ground states of chemical systems. Hardness results and the lack of efficient
heuristics for initial-state generation sheds doubt on the feasibility. Here we
propose an inherently efficient approach for solving chemical simulation
problems, meaning it requires quantum circuits of size scaling polynomially in
relevant system parameters. If a set of assumptions can be satisfied, our
approach finds good initial states by assembling initial states for dynamical
simulation in a scattering tree. We discuss a variety of quantities of chemical
interest that can be measured based on quantum simulation, e.g. of a reaction,
succeeding the initial state preparation.
