Since the beginning of his career, Professor Vértes has been very much interested in the field of interaction of nuclear radiation with matter. Back in 1962, when he first read Rudolf Mössbauer’s papers originally published in 1958, he was glad to discover that the Mössbauer effect is also a phenomenon based on the interaction of gamma radiation with matter.

Speaking of historical times, we should mention that the first Mössbauer laboratory in Hungary was built by Professors Lajos Keszthelyi and István Dézsi at the Central Research Institute for Physics (CRIP) in the early 1960s. Attila Vértes got his first chance to have a closer look at the technique of Mössbauer spectroscopy (MS) in that laboratory in 1966. Although affiliated with Eötvös Loránd University (or ELTE, as is widely known in Hungary) at that time, he took a handful of rusted iron and kept spending afternoons for a few months in CRIP’s “Mössba’ lab,” where István Dézsi taught him how to record the Mössbauer spectra of rust. The result of these daily excursions was the first publication showing that MS is an excellent tool to study the corrosion of iron. Since then, the Mössbauer Effect Data Center has registered about 1,000 MS papers on corrosion. Professors Keszthelyi and Dézsi also used MS for the investigation of frozen solutions, and Attila Vértes grabbed the opportunity to learn this technique as well.

Professor Glenn T. Seaborg (in the middle) in his den, with Professors László Guczi (left) and Attila Vértes (right). Photo taken in Berkeley in 1993.

Japanese-Hungarian team at SPring-8 during the Nuclear Inelastic Scattering measurements of the aqueous solutions of iron(II)-coordination complexes. Photo taken in May 1999.

In the next year (1967), Dr. Vértes managed to build a Mössbauer laboratory at the Chemistry Department of Eötvös Loránd University (with the help of electronic engineer János Soós). The applications of MS in different fields of chemistry (solution chemistry, coordination chemistry, corrosion, etc.) started in that laboratory. One of the first works of the new laboratory called the attention of Mössbauer spectroscopists to the very significant effect of the number of crystal water molecules in iron(II) salts on the Mössbauer parameters of the ⁵⁷Fe probe.

Dr. Vértes got his second great chance to study Mössbauer spectroscopy at N. N. Greenwood’s Institute in Newcastle (England) in the summer of 1969. There, he was able to work with the Mössbauer active nuclide ¹⁵¹Eu and, as a “compensation,” he taught Professor Greenwood’s co-workers how to record the Mössbauer spectra of frozen solutions. This cooperation – that can also be considered as an export-import business of ideas related to radionuclides – resulted in a publication on the MS of the frozen solution of some ¹⁵¹Eu salts.

Professor Vitalii Goldanskii happened to give a talk at the ICAME meeting in Tihany (Hungary) on positron annihilation spectroscopy (PAS) in August 1969. After that lecture, Attila Vértes decided to build a PAS laboratory as well. Béla Lévay, his colleague at ELTE, joined this plan and now Professor Lévay is an internationally recognized expert on positronium chemistry. Professor Vértes also published 65 PAS papers, partly together with Professor Lévay. Professor Vértes, in cooperation with Professor Philipp Gütlich, successfully used the PAS method for the study of the mechanism of spin-crossover in a few iron(III)-coordination compounds.

Two Japanese fellows: Philipp Gütlich (right) and Attila Vértes. Photo taken in Fukuoka in 1997.

The third important “field trip” for Attila Vértes was to Garching (Germany) between October 1969 and April 1970. Professor Mössbauer gave him the opportunity to record the Mössbauer spectra of about 50 frozen aqueous solutions of salts and complexes of iron(III) at the temperature of 4.5 K. (At that time it was very difficult to obtain liquid helium in Hungary.) The output of these measurements provided useful information for solution chemistry. If, e.g., enriched ⁵⁷Fe was used in the solutions and therefore the iron-concentration could be kept low (<0.05 M) and the pH was also very low (pH ~0) then, due to the slowness of paramagnetic spin relaxation, the Mössbauer spectra showed magnetic splitting. The measure of the effective magnetic field gave information about the chemical interaction between the central iron(III) cation and its first ligand sphere as well. If the intensity of this interaction increased, the effective magnetic field decreased. When the pH of the aqueous solutions was increased (pH >2), dimerization took place and therefore the magnetic splitting collapsed due to the fast spin-spin interaction and relaxation in the dimers. Thereafter, this Mössbauer technique was repeatedly used by Attila Vértes to follow the dimerization in iron(III) solutions. Ageing can result in polimerization in these solutions and, consequently, superparamagnetic particles can form, the size distribution of which can be determined from the temperature dependence of the paramagnetic to magnetic area ratio in the Mössbauer spectra. This possibility was also made use of in a few publications.

On the basis of the measurements in Garching, Dr. Vértes prepared a dissertation on “Mössbauer studies on the chemical structure of solutions,” for which he received the title Doctor of Sciences of the Hungarian Academy of Sciences in 1973. In 1974, he became a full professor of Eötvös Loránd University in Budapest. In 1983, he founded the Department of Nuclear Chemistry at the Faculty of Science of ELTE.

Professors Attila Vértes and Kálmán Burger began a long-lasting cooperation in the early 1970s on the applications of MS for coordination chemistry. They published more than 50 papers together, and worked out a technique to record the Mössbauer spectra of liquids containing Mössbauer active elements at room temperature.

ICAME-1995, Rimini. (Professor Kálmán Burger is in the middle of the photo.)

To achieve this, small drops of the liquid (~4 nm in diameter) were trapped in the pores of a piece of thirsty glass, and so the Mössbauer spectra could be measured at room temperature. This method, called Capillary Mössbauer Spectroscopy, was published in 1983 [                 Nature,                 306, 353 (1983)]. This fruitful cooperation continued until 2000, when Professor Burger died. (Professor Burger was a world-renowned expert in coordination chemistry.)                
               
   

Professors Henry Leidheiser (80), at center, Sándor Nagy (right), and Attila Vértes (left). Photo taken in Budapest, 1999.

Professor Henry Leidheiser (Professor of Lehigh University and Director of the Center for Surface and Coating Research) invited Professor Vértes to Lehigh to become a guest professor in 1976. Since then, they have managed to work out together several pioneering methods based on MS for the study of electrochemical and corrosion processes, as well as for the investigation of the composition and structure of the “interphase” between polymer coatings and metal substrates.

For instance, by performing “ex-situ” and in-situ measurements with                 ¹¹⁹Sn, they determined the composition of the passive layer of tin electrode during its polarization and proved the existence of the Sn                 ^II state as well. (Note that to record a single in-situ Mössbauer spectrum took about one month!)

In another series of experiments, they used the in-situ ⁵⁷Co emission technique. The Mössbauer hyperfine field parameters measured in a buffered borate solution (pH =8.5) after polarization at –100 mV (vs. saturated calomel electrode) were characteristic of Co(OH)₂, while the passive film obtained by polarization in the region of +200 mV to +500 mV provided parameters characteristic of β-CoOOH. At the polarization potential +600 mV, the emission Mössbauer spectrum indicated the presence of β-CoOOH and CoO₂ with the ratio of 1:2. At the potential +900 mV, the spectrum showed only one component: CoO₂. Exposure of CoO₂ to air resulted in Co₃O₄. This cooperation stopped, however, when Professor Leidheiser retired in 1990. Later on, these studies were resumed in cooperation with Professors Colin Chisholm and Mahmoud El-Sharif (Glasgow Caledonian University) and with Giovanni Principi (Padova University).

Attila Vértes 2004

During the last one and a half decades, Professor Vértes has focused his efforts on the Mössbauer study of perovskites and spinels showing high-T_c superconductivity and colossal magnetoresistivity (CMR). The main partner in these studies was Professor Amar Nath (Drexel University, Philadelphia). ¹⁹³Ir and ⁵⁷Fe Mössbauer studies of iridium and iron coordination compounds with fullerene ligands were also subjects of his interest in the 1990s. (The ¹⁹¹Ir Mössbauer measurements were carried out in collaboration with Professor Friedrich Wagner, i.e., the ¹⁹¹Ir spectra were recorded in Garching.)

Professor Vértes became a Corresponding Member of the Hungarian Academy of Sciences in 1993. He gave his inaugural address on “Positronium Chemistry.” He received the title of Ordinary Member of the same Academy in 1998. His inaugural lecture bore the title “Mössbauer spectroscopy of coordination compounds with fullerene ligands.”

Professor Vértes became an Honorary Doctor of Glasgow Caledonian University (England) in 1996. He was awarded the Széchenyi Prize, given by the President of the Republic of Hungary, in 2001. He is a member in the Committee of Radiochemistry of the Hungarian Academy of Sciences (Chairman between 1993 and 2002), as well as in the Division of Inorganic and Physical Chemistry. He is a past Member of the International Board on the Applications of the Mössbauer Effect (IBAME, 1990-1998), and holds editorial positions for some of the journals in the field.

Honorary Doctor of Glasgow Caledonian University (third from the left) and a few members of the Senate of the University (1996).

Professor Vértes was awarded the Hevesy Medal at the Opening Ceremony of the Conference of Modern Trends in Activation Analysis held in Guildford (England), June 21-25, 2004. This Medal is given by the Editorial and Advisory Board of the Journal of Radioanalytical and Nuclear Chemistry.

He is the author and/or editor of 12 monographs and textbooks in the field of nuclear and radiochemistry, including Mössbauer spectroscopy and positron annihilation spectroscopy for nuclear radiochemical analysis. His textbook “Nuclear and Radiochemistry” (Elsevier, Amsterdam, 1987, co-author: I. Kiss) has been used extensively for teaching purposes. The monograph A. Vértes, L. Korecz, K. Burger: Mössbauer Spectroscopy (Elsevier, Amsterdam, 1979) has been used by practicing Mössbauer spectroscopists and by many of those interested in becoming a research worker in this field.

At the same desk in 1980 and 2004: Erno Kuzmann and Attila Vértes.

Professor Vértes is the Editor-in-Chief of the recently published five-volume, 48-chapter, 2,500-page “Handbook of Nuclear Chemistry” (                                         Kluwer, Dodrecht, 2003). Professor Vértes’s work has been supported and helped by his colleagues at Eötvös Loránd University – Professors Béla Lévay, Sándor Nagy, Ernô Kuzmann, Ilona Czakó Nagy, Zoltán Homonnay, and Károly Süvegh; by his occasional, however important, partners in science – Professors Todor Peev (Bulgaria), Svetozar Music (Croatia), Yusuke Ujihira, Yoshimasa Takashima, Tetsuaki Nishida, Kiyoshi Nomura, and Yonezo Maeda (Japan), and Alexander Kamnev and Yurii Perfilev (Russia); as well as by his numerous students and postdoctoral fellows – e.g. Dr. Zoltán Klencsár, Dr. Tamás Marek, Zoltán Németh, and Krisztina Kovács in the last few years.

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The sources of the forces: Professor Vértes' grandson Csaba, age 9, and mother Erzsébet, age 90.