Dr J. Oomens (1968) has been named Professor by Special Appointment of Action Spectroscopy at the Faculty of Science of the University of Amsterdam (UvA). The chair was designated on behalf of the Physica Foundation (Stichting Physica).

Jos Oomens developed a method that uses a free-electron laser to measure the infrared spectra of mass-selected ions in a mass spectrometer. These spectra can be used to infer the molecular structure of the ions, which is generally not possible using just the mass spectrum or standard spectroscopic methods. Oomens' method has found wide application in mass spectrometry; at the Free Electron Laser for Infrared eXperiments (FELIX) facility at the FOM Institute for Plasma Physics Rijnhuizen, various projects are conducted in collaboration with guest researchers from the United States and Europe. Oomens currently focuses on further developing spectroscopic methods using FELIX, as well as on further applying these methods in different fields of chemistry.

Oomens has been at the FOM Institute for Plasma Physics in Nieuwegein since 1999, first as a researcher and later as head of the Molecular Dynamics Group. Previously he was researcher at the Gadja Mada University in Yogyakarta (Indonesia) and at the Radboud University Nijmegen. In 2007, a US-Dutch research consortium including the research group of Oomens was awarded a National Science Foundation (NSF) Partnerships for International Research and Education grant.