The Spectroscopy and Dynamics Group (SDG) of the Royal Society of Chemistry (RSC) notes the passing of Mike Hollas on 20 March 2025. Mike was a stalwart of the UK molecular spectroscopy community and a great supporter of the SDG. 

Mike was born in 1934 and was educated at Giggleswick School, then Heckmondwike Grammar School in Yorkshire prior to undergraduate studies at University College London (UCL), from whence he graduated with a first class honours degree in 1956. He remained at UCL for postgraduate research, exploring the electronic spectroscopy of gas phase aromatic molecules (benzene, naphthalene) with David Craig, and duly gained his PhD in 1959. Mike then embarked on postdoctoral research at the National Research Council in Ottawa – a well-trodden path for aspiring spectroscopists at that time – before being appointed to a Lectureship in Chemistry at the University of Reading in 1964. Mike was subsequently promoted to Senior Lecturer and to Reader and served the University of Reading for 32 years up to his retirement in 1996. 

Mike and his students published more than 100 scientific papers devoted to aspects of molecular electronic spectroscopy. Mike will, however, probably be best known among current SDG members for his textbooks. The first, Symmetry in Molecules, was published by Chapman and Hall in 1972. A German language version followed in 1975. High Resolution Spectroscopy, an advanced level tome, first appeared in 1982 (published by Butterworths) and an acclaimed more-undergraduate-focussed book Modern Spectroscopy followed (Wiley, 1^st edition 1987, 2^nd edition 1991, 3^rd edition, 1996).

‘Retirement’ gave Mike time to polish and update these texts further – the 2^nd edition of High Resolution Spectroscopy appeared in 1998 (now published by Wiley) and the 4^th edition of Modern Spectroscopy appeared in 2004. Mike also found time to write an RSC primer Basic Atomic and Molecular Spectroscopy, in 2002. Mike continued to support the SDG long after his retirement, and for many years generously donated copies of his major texts as prizes to be awarded to early career researchers judged to have given the most meritorious poster presentations at the annual SDG meeting. Away from spectroscopy, Mike joined the Henley Volunteer Bureau in 1998, became their fundraising officer the following year, and served as a Henley Volunteer Driver (providing transport for those unable to use public transport who need to attend essential medical appointments in the Henley-on-Thames area) through till July 2021. More mature members of the SDG will remember Mike fondly, as an exceptionally knowledgeable spectroscopist and a kind and patient gentleman.  

Text by Prof. Mike Ashfold FRS