The digital computer is an instrument which is in use in most, if not all, scientific fields and disciplines. Hence one can ask in what ways these disciplines have been affected. This talk wants to investigate how the organization of expertise, the conception of computational models, and computing technology bond to each other. The claim is that if one wants to specify this bonding, computational technology crucially matters - in particular the differences between big mainframe machines - which slowly came in use from the mid 1950s onwards - and smaller, networked computers that kickstarted around 1990. To specify this claim, I will concentrate on the case of quantum chemistry. Two phases will be discerned. The first leads to the establishment of quantum chemistry as a sub-discipline of chemistry. This process has been well-researched by M. Nye, K. Gavroglu, A. Simões, among others, who acknowledge the important role that the digital computer played for making quantum chemistry computationally feasible. However, this role does not follow a mathematical necessity, rather is subject to change. I want to discuss how the mainframe type of computer was related to a particular way of organizing expertise. The main issue of my talk will be the turn from quantum chemistry to computational quantum chemistry (CQC) that took place around 1990. In particular, so-called density functional theory will be investigated that came to play a major role in connection with CQC. It will be argued that the technology of lab-scale, networked computers links to a new "combinatorial" conception of computational modeling and to a market-like organization of CQC-expertise. The process of augmentation discussed here - turning quantum chemistry into "computational" quantum chemistry - might be seen as exemplifying parallel developments where other scientific fields are becoming "computational".