Discoveries and innovations of Moldovan researchers

In regard to the 70th anniversary from the establishment of the first research institutions and the 55th from the inauguration and establishment of the Academy of Sciences of Moldova, we are launching a series of articles on the discoveries and innovations of Moldovan researchers and their resonance. The first presentation from the series, as related by academician Gheorghe Duca, is the discovery of academician Isaac Bersuker of a new type of movement of atoms and molecules.

A new type of movement of atoms and molecules – academician Isaac Bersuker and his Discovery

Acad., Prof. Isaac Bersuker from the Institute of Chemistry of the Academy of Sciences of Moldova, studying the problems of the influence of the electronic structure of molecules and crystals on the configuration and dynamics of nuclei movements, has discovered the effect of tunneling splitting of energy levels of polyatomic systems in degenerate states. The discovery has been reviewed and endorsed in the top ten of most advanced research institutions of the ex-USSR, in the divisions and Presidium of the Academy of Sciences, and was registered in 1978 in the State Register with the number 202.

The discovery is of fundamental origin – a new type of motions in molecules and crystals was discovered – the so-called „pulsating motions” – when, under specific conditions, the molecules or atomic centers in crystals undergo spontaneous distortions in different directions with relatively high frequency. As a result, some substances gain new special properties, which manifest themselves quite strongly under external perturbations. These specific movements of atoms affect all the physical and chemical properties of substances. Due to its fundamental nature, the discovery of Acad. I. B. Bersuker opens new areas of research and underlies scientific searches for new materials and new properties of substances.

The discovery of academician I. B. Bersuker contributes to the understanding of the origin of specific properties of matter and mechanisms of physical, chemical, and biological processes (in literature all applications in this field are grouped under a more common name of the Jahn-Teller effect in which the discovery is an important part). With regard to such fundamental discoveries, it does not make much sense to talk about their „practical applications” – all the science-based innovations, all the search for new materials and new applications are based on such discoveries.

Examples of using the discovery in creating new materials:

1. It was shown that in molecules and crystals in the presence of “pulsating motions", predicted by the discovery, certain properties are enhanced in giant proportions. For example, in the crystal of barium titanate BaTiO3 the dielectric constant increases by thousands times. A similar increase is predicted for flexoelectricity (the appearance of the charges and the electric current under the influence of deformations) and electrostriction. All these new, previously unknown properties of substances are confirmed by experimental data, creating an important basis for the search for new materials.

2. There were identified molecules and crystals with bistable magnetic-dielectric properties, which are switched from a dielectric to magnetic under external influence - a property that is important for information storage elements (examples: CuF3, LiCuO2).

3. The conditions are formulated, when in perovskite-type crystals АВО3 ferroelectric and magnetic properties can coexist. Such crystals – „multiferroics” (example: BiFeO3), are important for applications in electronics.

An example from biology:

Understanding the molecular motion micromechanisms, taking into account the discovery, allows one to reveal the mechanisms of biological processes. For example, it was shown how the displacement of the iron atom from the plane of the porphyrin ring in hemoglobin in the absence of oxygen and its return to the plane during the oxygenation (similar to "pulsating motions") initiates conformational transitions which explain its functioning.

The discovery of I. B. Bersuker is included in dozens of monographs in the sections on the Jahn-Teller effect, which is studied in all high-level universities across the world. He has published more than 400 original research papers, which had over 10000 citations in literature.

Academician Gheorghe Duca,
President of the Academy of Sciences of Moldova