From 1961 he worked at the Ruđer Bošković Institute, where he held positions as Research Assistant (1961–1963), Senior Research Assistant (1964–1968), Research Associate (1968–1972), Senior Research Associate (1972–1977), and Research Advisor (from 1977). Since 1968, he was also Head of the Laboratory for Chemical Kinetics and Atmospheric Chemistry at the Division of Physical Chemistry.
At the same time, he taught at the Faculty of Pharmacy and Biochemistry (1970) and at the Faculty of Science, University of Zagreb (1971–2002). From 1970 he participated in postgraduate teaching at the University of Zagreb’s Centre for Postgraduate Studies, and later at the Faculty of Science. He also lectured at the Faculty of Natural Sciences and Technology in Ljubljana and collaborated with the Jožef Stefan Institute.
He frequently stayed at the Nuclear Research Centre in Karlsruhe, where already as a student (1959/1960), under D. Schulte-Frohlinde, he completed his diploma thesis “Measurement of the Quantum Yield of the Photoreaction of Bis-naphthyl Indigoid”, which was published in Chem. Ber. 94 (1961) 2382. At the same institution, he completed his postdoctoral training (as a theoretical organic chemist at the Institute for Radiation Chemistry, 1966–1968). Between 1972 and 1984, he also worked there intermittently within several bilateral projects with Germany in spectroscopy, theoretical chemistry, and atmospheric chemistry. At the Department of Chemistry, Louisiana State University in Baton Rouge, as Visiting Professor (from 1984 onwards), he worked in laser and mass spectrometry and taught biophysical chemistry.
He introduced programming and computer applications into undergraduate and postgraduate chemistry studies at the University of Zagreb. His research focused on physical-organic, atmospheric, and theoretical chemistry, as well as mathematical methods in chemistry, mass, photoelectron, and laser spectroscopy. He achieved valuable results in studying the electronic structure of small molecules and was the first to obtain high-quality photoelectron spectra of many important groups of biologically active molecules (amino acids, opiates, steroids). He introduced ionization potential as a parameter for determining compound activity. He was also the first in Croatia to develop and organize atmospheric chemistry research, particularly on tropospheric ozone.
Together with Zvonimir Maksić and Nenad Trinajstić, he co-authored the textbook Symmetry of Molecules (Zagreb, 1979). He became a corresponding member of the Croatian Academy of Sciences and Arts (HAZU) in 1990 and a full member in 2004. He was awarded the Ruđer Bošković Prize (1987), the HAZU Award (1996), the City of Zagreb Award (2002), and the Lifetime Achievement Award (2007).
For his contributions to science and his role in education, in 2005 he was awarded the honorary title of Distinguished Scientist of the Ruđer Bošković Institute.
