Frank recorded more ¹²⁵Te Mössbauer spectra from organotellurium compounds in the summer of 1975 at Simon Fraser University in Vancouver, Canada, before returning to England in October 1975 to take up an ICI Research Fellowship at The University of Cambridge.

This proved to be a defining time in Frank’s career, as it initiated the main thrust of Frank’s work over the next 15 years on the chemical, structural, and surface properties of various solid materials, with particular attention being given to metals and metal oxides. The work involved the use of several techniques, but it was during his time in Cambridge that Frank became inspired by the potential of Mössbauer spectroscopy, largely as a result of collaborating with Dr. Alfred Maddock, whom Frank still considers as the most gifted and inspirational scientist, with an encyclopedic knowledge of chemistry and feeling for the subject, that he has ever encountered. During his time in Cambridge, Frank studied the nature of supported small α-Fe                     2O                     3 particles and their reduction properties and developed a conversion electron Mössbauer detector for examining the nature of the surface phases formed on iron when chemically treated by various phosphating processes, and which demonstrated the unusual stability to oxidation of thin films of iron(II)phosphate octahydrate when formed on metallic iron. Subsequent investigations in this area considered the nature of corrosion- and abrasion-resistant surfaces produced on metallic iron by treatment with sulphide, cyanide, and thiocyanate and how the stability of different phases depended on the nature of treatment and the underlying substrates.

Frank and Alfred Maddock, taken in 1978 at the First Seeheim Workshop in Chemical Applications of Mössbauer Spectroscopy

These studies by Mössbauer spectroscopy of supported particles and chemically treated surfaces were relevant to industrial interests in catalytically active solids where the nature of the surface, which frequently depends on the preparative procedure and the bulk structural properties, may change when treated in a gaseous environment. Work was therefore initiated on tin-antimony oxide catalysts, which are active for the catalytic oxidation of hydrocarbons. The ¹¹⁹Sn- and ¹²¹Sb-Mössbauer spectra showed the technique to be a sensitive means by which changes in oxidation state of two elements in a mixed oxide catalyst could be monitored and the special power of ¹²¹Sb Mössbauer spectroscopy for examining the oxidation states of antimony at solid surfaces.

By this time it was 1978, and two events happened that year that were very important to Frank in terms of his subsequent career.

Frank and Örn Helgason, taken in 1999 at the ICAME held in Garmisch-Partenkirchen.

The first event was the First Seeheim Workshop in Chemical Applications of Mössbauer Spectroscopy, where Frank met the international “Mössbauer family” for the first time. The ethos of Seeheim struck a chord with Frank – everyone living under the same roof in a most beautiful forest location in Germany with time to listen to lectures, talk with other scientists, enjoy the countryside, and meet people of the same generation, some of whom remain his friends today.

The second event was that in 1978 Frank was offered a Lectureship at The University of Birmingham, which enabled him to develop the work he had initiated in Cambridge. Hence, in October 1978, Frank and his family moved to Birmingham where he was subsequently promoted to Senior Lecturer and later to Reader in Solid State Chemistry, and there he stayed until 1991.

The 13 years in Birmingham were very important to Frank. He built up a small research group of around eight people and developed methods to exploit the special power of the high energy Mössbauer gamma-rays, which can readily penetrate gaseous environments and thereby examine catalysts in their authentic working environments. Hence the in situ study of small particle metallic and bimetallic catalysts that can be used for the hydrogenation of carbon monoxide became a major thrust during the early years in Birmingham. The results were interpreted in terms of how changes in cationic oxidation states, metal-metal interactions, and metal-support interactions can be correlated with catalytic performance. At the same time, new work into the chemical, structural, and surface properties of catalytically active titanium-antimony oxides, nickel-uranium oxides, iron-zirconium oxides, vanadium antimonate, iron antimonate, and tin molybdate were initiated. This work entailed the use of X-ray-, neutron-, and electron-diffraction, as well as XPS and Mössbauer spectroscopy, to study the ranges of stoichiometry in these systems, the occurrence of cationic order, defect structures, and enrichment of surfaces. The identification of spin glass properties, cationic order, and a superlattice in iron antimonate which had previously been described as containing a random distribution of cations and of the segregation of molybdenum to twin boundaries in tin molybdate attracted attention at the time.

Towards the end of the 1980s the focus of work was extended to superconducting oxides [M₂CuO₄ (M = La,_, Eu, Sr)] metal molybdenum chalcogenides (Mo_6-xM_xX₈ (M = Ru, Rh, X = S, Se, Te) showing the co-existence of magnetic order and superconductivity, low dimensional solids, and tin oxide-pillared clays. It was also a time when Frank began using in situ synchrotron EXAFS techniques to elucidate structural changes to complement in situ Mössbauer spectroscopy evidence for oxidation state changes in catalytically active small particles. The power of EXAFS and XANES became evident in studies of iron-iridium, iron-ruthenium, nickel-uranium oxides, and nickel-thorium oxides and the use of synchrotron radiation was to become an important strand in Frank’s subsequent work in the 1990s. It was also in the late 1980s that work was initiated on niobium titanium phosphates (NbTiP₃O₁₂) with nasicon-related structures. The combination of diffraction techniques, Mössbauer spectroscopy, and EXAFS proved valuable in locating large ions such as tin and iron incorporated within the three dimensional channel type structures of these materials, and this area of interest persisted well into the early 1990s.

In 1991 Frank was appointed as Professor of Inorganic Chemistry at The Open University where, between 1992 and 1996 and between 1999 and 2002, he was also Head of the Chemistry Department. The initial research in the early 1990s saw the development of studies of materials with nasicon-related structures and the expansion into studies of rare-earth-exchanged Y-zeolites. Again, the use of diffraction techniques for structural characterisation and of Mössbauer spectroscopy and EXAFS and XANES for the identification of local coordination and cationic oxidation states were important approaches in the study of these materials. It was also a time of initiating new work, in using hydrothermal processing for the synthesis of small particle aluminosilicates to be studied by diffraction, solid state NMR spectroscopy, and EXAFS.  Iron oxide pillared clays were made by microwave heating and examined by Mössbauer spectroscropy. Magnetic order in new garnet systems of the type YCa₂SbFe₄O₁₂, of hexaferrites of the type Sr_1-xM_xFe₁₂O₁₉ (M = Ca, Eu), and bonding in Zintl Phases also became the subject of study by diffraction methods, EXAFS, and Mössbauer spectroscopy.

Three other major areas developed in the 1990s: one involved the use of Mössbauer spectroscopy to examine the weathering and characterisation of meteorites, and another the study of metal doped iron oxides by diffraction, EXAFS, computer simulations, and, importantly, high temperature Mössbauer spectroscopy. The diffraction and computer modelling studies identified new defect structures, but it was the high temperature Mössbauer studies which elucidated structural changes which occur at elevated temperatures and how they are related to changes in magnetic order.

Frank and Ramon Gancedo, taken in 2002 at the Mössbauer Spectroscopy in Materials Science meeting held in Smolenice, Slovakia.

The unusual stabilisation of  γ-Fe₂O₃ to transformation to α-Fe₂O₃ was identified and rationalised. A third area has been the use of mechanical milling to make small particle oxides and sulphides and the use of Mössbauer spectroscopy to study the evolution of magnetic structure in, for example, ZnFe₂O₄ made by the milling of iron- and zinc-oxides. At the same time, studies of nickel-cobalt-oxide systems, lithium insertion into oxides, Co/Fe multilayers, and the reduction properties of orthoferrites have been performed. At the present time Frank is developing an interest in the synthesis of new fluorinated perovskite-related oxides by low temperature routes. The structural characterisation of these materials by diffraction methods and the characterisation of their magnetic properties by Mössbauer spectroscopy are currently proving to be challenging.

Frank’s scientific interests have spanned chemistry, physics, and materials science. He has co-edited two books (one on Mössbauer spectroscopy, first published in 1986 and published in paperback form by Cambridge University Press in 2005) and is Editor of The Royal Society of Chemistry Annual Reports on the Progress of Chemistry.

Frank holds in high esteem the large number of students, postdoctoral workers, and visitors who have worked with him over the past 30 years – without them none of the really exciting work would have been done. He is also indebted to the people with whom he has collaborated, who he has visited, who have visited him, and who are now friends of Frank and his family and who have enriched his life.

Frank, Steen Mørup, Philipp Gütlich, and Guido Langouche during a meeting in Leuven on the new constitution for IBAME.

Frank has served on many national and international committees over the years. In the late 1990s he chaired the group which made the scientific case for a new synchrotron (DIAMOND) which is currently being built in the UK, he chaired the Synchrotron Radiation Source Forum for several years, and has been a member of various committees of the UK’s research funding organisations. However, the positions he has enjoyed most are those involved with Mössbauer spectroscopy, both the Royal Society of Chemistry Mössbauer Group, of which he has been a leader for many years, and also the International Board on the Applications of the Mössbauer Effect (IBAME). Frank, together with Philipp Gütlich, Steen Mørup, and Guido Langouche, formulated the constitution for IBAME in the early 1990s, and he considers his current role as Chairman of IBAME as the greatest honour he has had bestowed upon him.