Exploring the invisible world of molecular interactions through seven decades of pioneering research
Imagine if you could witness the secret social lives of molecules—how they meet, interact, and form new relationships in fractions of a second. This hidden dance of particles drives everything from photosynthesis to quantum computing, yet remains invisible to the naked eye.
For seven decades, one scientist has served as our foremost interpreter of this microscopic world: Kev Minullinovich Salikhov, a pioneer who transformed our understanding of how molecules behave by reading their magnetic signatures. His work, spanning from the depths of Soviet science to international recognition, reveals how the faintest magnetic whispers between particles can determine the outcome of chemical reactions that shape our world.
Salikhov's career represents an extraordinary bridge between fundamental physics and practical application, demonstrating how curiosity-driven research can illuminate everything from industrial processes to the very mechanisms of life itself. As we celebrate his seventieth birthday, we explore the legacy of a man who learned to listen to what molecules were saying through their spin—and in doing so, founded entirely new fields of scientific inquiry.
Studied under Professor S.A. Altshuler1 and began his scientific journey.
Completed postgraduate studies focusing initially on the physics of polymers.
Began working at the Institute of Chemical Kinetics and Combustion1 .
After 3-4 years, began actively working in electron paramagnetic resonance spectroscopy1 .
Salikhov's 25-year period in Novosibirsk produced foundational work that would define multiple subfields of magnetic resonance, establishing him as a leading theorist in spin systems dynamics.
"Not immediately, but after 3-4 years I began to actively work in the field of electron paramagnetic resonance (EPR) spectroscopy. As a theoretical physicist, I got an opportunity to make a real contribution to the basics and development of pulse EPR spectroscopy, to lay the foundations of spin chemistry. Everything was going well."1
Spin chemistry explores how the quantum mechanical property of "spin" influences chemical reactions and processes. At its simplest, electrons and atomic nuclei can be thought of as tiny magnets that can align or oppose external magnetic fields. When molecules interact, the spin states of their electrons can determine whether reactions proceed or stall—a phenomenon that Salikhov helped decode through both theoretical and experimental breakthroughs.
The intrinsic angular momentum of elementary particles
Awarded for fundamental contribution to the theory of magnetic and spin effects in radical chemical reactions1 .
Foundational work on the theory of pulse EPR spectroscopy1 that enabled new experimental approaches.
Pioneering contributions to the theory of spin exchange and the method of spin probes1 .
His work on the magnetic isotope effect demonstrated that even isotopes of the same element, differing only in their nuclear spin properties, could exhibit dramatically different chemical behavior5 . This revealed how subtle quantum properties can influence macroscopic chemical processes.
In 1988, as Perestroika reshaped Soviet science, Salikhov faced a pivotal career moment. He was elected director of the Kazan E. K. Zavoisky Physical-Technical Institute (KPhTI), named after the scientist who first observed electron paramagnetic resonance1 . This homecoming to Kazan marked the beginning of a 27-year leadership period that would transform the institute into a world-class research center.
Under Salikhov's guidance, KPhTI diversified into new scientific directions including:
Despite administrative responsibilities, Salikhov continued his theoretical work:
"From the outset, I managed to inspire every scientist working at the institute, but also many people in Tatarstan, Russia, and abroad with the idea to make KPhTI one of the world's leading centers in EPR spectroscopy."1
To appreciate Salikhov's experimental contributions, we must first understand radical ion pairs (RIPs)—short-lived charged molecules that play crucial roles in many chemical processes, including photosynthesis. These pairs are born in a specific quantum state (singlet state) but can switch between different states (singlet and triplet) through a process influenced by both internal molecular properties and external magnetic fields.
Salikhov and colleagues developed a sophisticated approach called "time-resolved magnetic field effect with magnetic field switching" to study these elusive particles3 .
Using nanosecond X-ray pulses
To influence spin evolution
After controlled delays (100-225 ns)
| Parameter | Role in Experiment | Typical Values |
|---|---|---|
| Magnetic Field Strength | Must exceed EPR spectrum width | > Hyperfine coupling constant |
| Field Switching Delay | Controls initial spin state evolution | 100-225 nanoseconds |
| X-ray Pulse Duration | Creates radical ion pairs | 2 nanoseconds |
| Measurement Frequency | Balances signal quality with time resolution | 80 kHz |
The experiments, conducted on solutions of paraterphenyl in decane, revealed how hyperfine interactions and relaxation processes influence spin dynamics3 . By analyzing the ratio of fluorescence intensities with and without field switching, the team extracted precise parameters about radical ion behavior that were previously inaccessible.
This method proved particularly valuable for studying chemical reactions of radical ions occurring within the timeframe of spin relaxation, opening new windows into processes crucial for understanding energy conversion in biological systems and developing new materials for optoelectronics.
Throughout his career, Salikhov developed and refined numerous experimental and theoretical methods that became essential tools for the magnetic resonance community.
| Method/Technique | Function | Key Applications |
|---|---|---|
| PELDOR (Pulsed Electron-Electron Double Resonance) | Measures nanometric distances between paramagnetic centers | Structural biology, material science |
| Spin Exchange Theory | Describes how electrons transfer spin information during collisions | Understanding radical reactions, biological signaling |
| Spin Probes | Uses stable radicals to report on local environment | Polymer science, membrane studies |
| Time-Resolved Magnetic Field Effect | Tracks spin state evolution in radical pairs | Studying short-lived reaction intermediates |
| Theory of Magnetic Isotope Effects | Explains how nuclear spin influences chemical reactivity | Isotope separation, understanding biochemical selectivity |
Some of Salikhov's most impactful theoretical predictions concerned the primary steps of photosynthesis—how plants convert solar energy into chemical energy. He predicted that the initial charge separation in photosynthetic reaction centers would produce specific signatures in EPR spectra, including quantum beats of line intensity and an abnormal phase of the electron spin echo signal1 .
When these predictions received experimental confirmation, they provided crucial validation for our understanding of how nature harnesses quantum effects for energy conversion. This work exemplifies Salikhov's approach: developing rigorous theoretical frameworks that could then be tested and applied to explain fundamental natural processes.
His research group also made significant contributions to quantum information science:
This expansion into quantum computing demonstrates how foundational work in magnetic resonance continues to inform cutting-edge technologies.
Beyond his specific theoretical and experimental contributions, Salikhov's legacy includes fostering international collaboration in magnetic resonance research. He served as founding editor of the journal "Applied Magnetic Resonance" (now in its 52nd volume) and established the International Zavoisky Award for outstanding contributions to EPR spectroscopy1 .
His efforts positioned Kazan firmly on the map of magnetic resonance conferences, most notably hosting the AMPERE Congress in 1994—the first time this prestigious meeting was held in Russia1 .
Despite geopolitical challenges, Salikhov maintained strong scientific relationships with colleagues in Germany, particularly with the research group of Klaus Möbius at the Free University of Berlin.
"Your enthusiasm for your research and the worldwide community of scientists is unprecedented. You made the Kazan Physical-Technical Institute in Kazan a worldwide recognized center of EPR spectroscopy and its members spread around the globe."1
| Award/Honor | Year | Significance |
|---|---|---|
| Lenin Prize | 1986 | For work on magnetic and spin effects in radical reactions |
| Election to Russian Academy of Sciences | Not specified | Recognition as top expert in spin systems dynamics |
| Vice-President, Tatarstan Academy of Sciences | Not specified | Leadership in regional scientific development |
| International EPR Society Silver Medal | Recent | Presented to his colleague E.G. Bagryanskaya, reflecting institute's status |
| Special Issue of Applied Magnetic Resonance | 2022 | Celebrating his 85th birthday alongside Klaus Möbius |
Even in his eighth decade, Salikhov remains actively engaged with the future of magnetic resonance. He continues to collaborate on Russian Science Foundation projects and maintains connections with colleagues across Russia and beyond1 . His current interests include establishing a Center for the Development of Science Methodology, focusing on the philosophical and organizational aspects of scientific progress.
When asked about the development of EPR spectroscopy in Russia compared to advances in Europe, the US, and China, Salikhov offered a characteristically insightful perspective: "Yes, there is such a situation with Russian scientific instrumentation in the field of magnetic resonance. But it did not arise because we cannot make such machines. The only question is whether we want to develop this direction."1 He points to examples like the pulse EPR spectrometer developed collaboratively in Tomsk as evidence that Russian science continues to innovate when there is sufficient will and resources.
Methodology, philosophy, and organization of science
Kev Minullinovich Salikhov's seven-decade journey through the world of magnetic resonance represents a remarkable convergence of theoretical brilliance, experimental innovation, and scientific leadership.
By learning to interpret the subtle language of electron spins, he has helped unravel mysteries ranging from the quantum mechanics of chemical reactions to the practical functioning of photosynthetic systems.
His career demonstrates that the distinction between fundamental and applied science is artificial—that deep curiosity about how nature works at its most fundamental level inevitably leads to practical insights and applications. As Salikhov himself expressed it: "The meaning of science is in the knowledge of nature. This requires fundamental research. Fundamental knowledge leads to the creation of new technologies."1
As we celebrate his seventieth birthday, we recognize not just a brilliant scientist but a builder of institutions, a mentor to generations, and a bridge between scientific cultures. The tools and theories he developed continue to enable new discoveries across physics, chemistry, and biology—proof that learning to listen to the faint magnetic voices of particles can ultimately help us understand some of nature's deepest secrets.