 Pople pioneered the development of more sophisticated computational methods, called ab initio quantum chemistry methods, that use basis sets of either Slater type orbitals or Gaussian orbitals to model the wave function.While in the early days these calculations were extremely expensive to perform, the advent of high speed microprocessors has made them much more feasible today.He was instrumental in the development of one of the most widely used computational chemistry packages, the Gaussian suite of programs, including coauthorship of the first version, Gaussian 70.