The unveiling on the Kumpula campus of the University of Helsinki on the 25 November, 2021, was attended by the chancellor of the University of Helsinki, Kaarle Hämeri, who accepted the portrait into the university's portrait collection, as well as family, friends, and colleagues of Halonen's.
The head of the Department of Chemistry, Professor Heikki Tenhu, gave an account of Halonen's lifetime achievements. Lauri Halonen was appointed professor of physical chemistry in 1992. Besides leading his own research group, he has been the director of the laboratory of physical chemistry and the research unit for molecular sciences (1992 - 2021). Further, he was the head of the 'Computational Molecular Science' Centre of Excellence of the Academy of Finland (2009 - 2011), the graduate school for computational chemistry and molecular spectroscopy (1998 - 2011), the doctoral programme 'Chemistry and Molecular Science' (2019 - 2021), and a highly valued project in the Academy of Finland programme 'Finland Distinguished Professor Programme' (2011 – 2015).
Professor Halonen is an internationally acclaimed researcher with a wide network of collaborations, who has worked at eminent research institutes around the world, such as ETH Zürich and the universities of Oxford, University College London, and Princeton, for a total of over ten years. His wide-ranging scientific work has focused on molecular spectroscopy, and he has combined computational methods with theoretical chemistry and experimental laser spectroscopy. He considered the development of new research methods important and has, besides carrying out basic research, brought in the latest methods of molecular spectroscopy into practical applications, such as medical diagnostics. Professor Halonen has published over 200 peer-reviewed articles, and over 20 PhD theses have been completed under his supervision. Further, he has been active in many national and international confidential and specialist posts, such as the steering groups of four different networks in the association 'European Cooperation in Science and Technology.' He has organised several valued international conferences in Finland, with speakers such as Nobel laureate in chemistry Harold Kroto and Nobel laureate in physics John Hall. Professor Halonen is a member of the Finnish Academy of Science and Letters and a corresponding member of Akademie der Wissenscaften zu Göttingen, as well as a member of the auxiliary committee of the journal Chemical Physics Letters.