  As quantum computing hardware systems continue to advance, the research and
development of performant, scalable, and extensible software architectures,
languages, models, and compilers is equally as important in order to bring this
novel coprocessing capability to a diverse group of domain computational
scientists. For the field of quantum chemistry, applications and frameworks
exists for modeling and simulation tasks that scale on heterogeneous classical
architectures, and we envision the need for similar frameworks on heterogeneous
quantum-classical platforms. Here we present the XACC system-level quantum
computing framework as a platform for prototyping, developing, and deploying
quantum-classical software that specifically targets chemistry applications. We
review the fundamental design features in XACC, with special attention to its
extensibility and modularity for key quantum programming workflow interfaces,
and provide an overview of the interfaces most relevant to simulations of
chemistry. A series of examples demonstrating some of the state-of-the-art
chemistry algorithms currently implemented in XACC are presented, while also
illustrating the various APIs that would enable the community to extend,
modify, and devise new algorithms and applications in the realm of chemistry.
