Brief Biographical Sketch of Tara Prasad Das
[For a more detailed Biographical Data please follow this link.]
Name: Tara Prasad Das
Citizenship: Citizen of USA.
Education: Bachelor of Science (Honors) from Patna University, India (1949); Master of Science, Calcutta University, India (1951); Doctor of Philosophy (Ph.D.), from Saha Institute of Nuclear Physics, Calcutta University, India (1955) with thesis entitled "Principles and Theory of Nuclear Magnetic Resonance Experiment".
Post-Doctoral, Permanent and Visiting Positions: Following my Ph.D. degree, for the period 1955-1961 I held post-doctoral positions for one year at Chemistry Department, Cornell University, one year at Physics Department, University of California Berkeley, one year as Reader (Associate Professor) at Saha Institute of Nuclear Physics at Calcutta University, one year each as Research Assistant Professor in the Physics Department at University of Illinois at Urbana and Research Associate in the Chemistry Department at Columbia University and one year as Senior Research Officer at Bhabha Atomic Research Establishment at Bombay (Mumbai), India.
The permanent positions I have held are Associate Professor and Professor, Department of Physics, University of California, Riverside (1961-`65) and (1965-`69) respectively, Professor, Department of Physics, University of Utah, Salt Lake City (1969-`71) and Professor, Department of Physics, State University of New York at Albany (1971 to the present).
I have also held visiting positions during sabbatical leaves and Summer breaks, as Visiting Professor or Research Scientist, at Department of Physics, Université Paris Sud-Orsay, France, Atomic Energy Research Establishment, Harwell, England, Institut Laue-Langevin in Grenoble, France, Institut für Physikalische Chemie, Technische Hochschule Darmstadt, Germany, University of Florida, Gainesville, Florida, Eidgenössische Technische Hochschule, Zürich, Switzerland, Institut für Atom Physik, Universität Mainz, Germany, Institute of Physics, University of Århus, Denmark, Faculty of Science, University of Tokyo, Japan, School of Physics, Central University of Hyderabad, India, Institut für Physik, Universität Zürich, Switzerland, Muon Science Laboratory, Institute of Physical and Chemical Research (RIKEN), Japan as Eminent Scientist, Meson Science Laboratory, High Energy Accelerator Research Organization (KEK) as Monbusho Senior Visiting Scientist, and Visiting Professorship in the Physics Department, University of Central Florida, Orlando.
Honors and Awards: US Senior Scientist Award, Alexander von Humboldt Foundation, Germany (twice); Yamada Science Foundation Award, Japan; Presidential Excellence in Research Award (SUNY at Albany); Jawaharlal Nehru Visiting Professorship, Central University of Hyderabad, India; Eminent Scientist Award at Institute of Physical and Chemical Research (RIKEN) Japan; Monbusho (Ministry of Science, Education, Culture and Sports, Japan) Visiting Foreign Scientist Award.
Membership in Professional Societies: Fellow, American Physical Society; Member of New York Academy of Sciences, Biophysical Society (US), National Society of Atomic and Molecular Physics, India and Orissa Science Academy, India
Research Interests: Ever since the start of my professional academic career about four and a half decades back, my research interests have been focused on the first-principle understanding of atomic, molecular, condensed matter (including bulk and surface properties and systems of interest in materials research) and biological systems to explain their geometric, spectroscopic (including optical, infrared, ultraviolet and X-ray), magnetic and hyperfine properties. The members of my research group including Ph.D. students interact closely with experimentalists, using our theoretical predictions of the relevant properties of systems with results of experimental measurement and in partnership with experimental groups to try to obtain and enhance the understanding of the mechanisms and factors contributing to the origins and natures of the properties involved.
The classes of systems my research group and I have been investigating over the years are: (I) Atomic Systems with emphasis on many-body effects on their magnetic, hyperfine and spectroscopic properties, (II) Small Molecules and some cluster systems, using first-principle procedures including many-body effects both for their intrinsic interest and also to test the method before applying them to relatively large biological systems and to the simulation of solid systems using large clusters, (III) Molecular Solids where we are interested in studying how well one can explain the properties of such systems by the single molecule components of such systems, and also the importance of the influences of intermolecular interactions including van der Waals effects on their properties of both the pure systems and systems containing impurity atoms or molecules, (IV) Biologically important molecules, especially hemoglobin derivatives and other heme based systems, reaction centers of systems involved in photosynthesis, and DNA systems, the interest being in the understanding of their hyperfine and magnetic properties as well as electron transport in these systems, (V) Physiologically and Energetically important Molecules where the interest is in the understanding of the origin of the nuclear quadrupole interactions in them using their electronic structures obtained through first-principle investigation of their electronic structures which would also be helpful in the understanding of their physiological effects on the body, (VI) Theoretical Study of the Contrast Agents in Magnetic Resonance Imaging involving transition metal and rare-earth ions and their related chemical compounds in aqueous solutions with respect to the number and geometry of water molecules liganded to them and the electronic structures and associated 1H and 17O hyperfine interactions. The latter are expected to be valuable in the understanding of the enhanced proton relaxivities in the presence of the contrast agents, (VII) The Study of Metallic systems and Hydrogen and Muon in Metals and Alloys using first-principle procedures for studying the electron distributions in them, using, in the seventies and eighties, first-principles band structure procedures to study Knight shifts in non-magnetic metals and hyperfine fields in ferromagnetic metals with our current interest being to use Hartree-Fock Cluster methods to study energetics for hydrogen and proton and also their surrogates, muonium and muon, and associated Knight shifts and hyperfine fields in metals and alloys at these light impurity sites and compare with the results of magnetic resonance and muon spin rotation measurements, (VIII) Semiconductors – Properties of Impurity Atoms including Muonium and Muon inside Semiconductors, our past work having involved study of muonium (hydrogen) and fluorine in diamond silicon and germanium, both locations, electronic structures and hyperfine interactions and comparison with experiment, our current work involving study of 69Ga and 14N quadrupole interaction in pure GaN and properties of muonium in this ionic semiconductor as well as in ZnO, all using the Hartree-Fock cluster procedure, (IX) Semiconductor Surfaces – Locations, Electronic Structures and Magnetic Properties and Hyperfine Interactions associated with adsorbed atoms and Influence of Reconstruction Effects on them. Our earlier work on properties of adsorbed atoms involved the study of a broad variety of such atoms without any reconstruction effects on silicon surfaces. The results of this study have led to experimental measurements of hyperfine effects associated with the nuclei of adsorbed atoms in reconstructed surfaces and we are currently trying to make quantitative comparisons with the available experimental data. Additionally, we are working on adsorbed muonium on silicon surfaces to check if the location of dilute muonium (hydrogen) atoms at the surface is similar or not to that for higher coverage of hydrogen atoms and also to compare predicted hyperfine interactions for surface muonium atoms with results of slow muonium mSR measurements when available, (X) Ionic Crystals – Electronic Structures, Magnetic and Hyperfine Properties of Ionic Crystals, both Perfect and Imperfect. Our earlier investigations in the 1960’s and 1970’s involved use of semi-empirical techniques involving Born-Mayer repulsions, Madelung, polarization effects on the ions and overlap effects on electron distributions to study nuclear quadrupole interactions and chemical shift effects in magnetic resonance in perfect and imperfect systems, color centers including both electrons (F-centers) and holes (VK-centers). Since 1980’s, we have used first-principle Hartree-Fock cluster procedures with the influence of ions outside the clusters being included by point charge and point dipole approximations, the properties studied again being hyperfine properties including also isomer shifts in Mössbauer spectroscopy, the perfect systems studied being superionic conductors, zinc compounds involving the chalcogenides and fluoride, zinc spinel systems and preliminary analysis of nuclear quadrupole interactions in nanostructured zinc oxide. Among the imperfect systems and properties we have studied are two-photon luminescence process in phosphors, the hyperfine fields at muon sites in the antiferromagnetic phases of transition metal oxides MnO and NiO, including dynamic effects. In all cases, comparisons have been made with available experimental results. Our present research studies and future plans involve continued efforts in perfect ionic crystals including many-body effects and larger clusters. The properties and systems being currently studied include additional work in the perfect systems including the zinc chalcogenides and fluoride and zinc spinels to enhance the agreement with experiment, continued study of nanostructured zinc chalcogenides and the spinel system ZnFe2O4 to further improve the agreement with experiment for hyperfine properties and nanostructured zinc systems, the projects for the latter systems to be briefly described under item (xv). Also slated for study are muon hyperfine properties in antiferromagnetic CoO and CuO where there are important experimentally observed differences with respect to MnO and NiO, (XI) Electron Distributions and Associated Magnetic and Hyperfine Fields in High-Tc Superconducting Systems – Our investigations in high-Tc systems have been, and continue to be, aimed at understanding their magnetic and hyperfine properties using first-principle investigations of their electronic structures. In our earlier investigations, we have studied hyperfine fields and nuclear quadrupole interactions in perfect materials, La2CuO4, YBa2Cu3O6 and YBa2Cu3O7 with overall good agreement with experimental results from nuclear magnetic resonance and quadrupole resonance measurements. We have also studied magnetic hyperfine fields at trapped positive and negative muons in La2CuO4, investigating their locations by first-principles energy optimization procedures (the latter found to be trapped near the apical oxygen) with the hyperfine fields at the muon sites in order of magnitude agreement with experiment but somewhat larger than experiment. Our current and future planned efforts are aimed at improving the agreement of the various hyperfine properties with experiment, including many-body effects and use of larger clusters and more flexible variational procedures for electronic structure investigations and also study of other systems like the two-chain YBa2Cu4O8 and TlCa Copper Oxide systems where interesting features have been observed for hyperfine properties. Additionally we plan to study the interesting hyperfine properties suggesting co-existence of magnetism and superconductivity associated with x » 1/8 in La2-xSrxCuO4 systems and charge and spin stripe structures observed by neutron scattering measurements. Similar hyperfine properties in the Sr doped Lanthanum Nickelate systems and associated stripe structures will also be investigated. It is hoped that the electronic structure investigations in these various high-Tc systems will not only provide quantitative explanations of the observed magnetic and hyperfine properties but will also be valuable for an eventual quantitative understanding of the mechanism(s) responsible for the origin of high temperature superconductivity, (XII) Organic Ferromagnets – These are systems that do not involve any transition metal atoms in contrast to conventional ferromagnetic systems, and have very low Curie temperatures of 1 K and less. Muon spin rotation (mSR) measurements have already been carried out in these systems and we have been able to show that in one particular system belonging to the class of systems referred to as TEMPO systems, one can explain the observed mSR frequency using calculated first-principle electronic structures and also determine the easy axis. This easy axis has been explained by magnetic dipole-dipole interactions between the spins in the free radical systems in the solid. We are currently investigating whether the dipole-dipole interactions can also explain the low observed Curie temperature. Similar investigations as we have carried out on TEMPO systems are also being carried out on other organic ferromagnets also involving no transition metal ions and on systems involving well separated clusters of transition metal ions in organic systems which can lead to high magnetic moments and in which mSR measurements have been recently carried out, (XIII) Problems associated with Muon Catalyzed Fusion – Our investigations in this field are concerned with trapping of m- by 3He+ in solid hydrogen, associated with the b-decay of tritium in pure solid tritium or in mixtures of solid deuterium and tritium. This trapping process can seriously undermine the chain reaction nature of fusion in these solid state systems involving m- within its life-time. For the purpose of understanding the trapping of m- by He+ in the solid hydrogen system, it is first very essential to understand the helium (He+) accumulation in solid hydrogen. We have carried out the corresponding investigation for He+ trapping in solid hydrogen and obtained important results regarding the relative strengths of trapping in solid and liquid hydrogen in agreement with experiment and also a number of other features for the trapping of He+. Our efforts in this areas are continuing with the trapping of other entities like (He-H)+ in addition to He+. Also slated for future quantitative investigations on trapping of m- by 3He+ and (3He-H)+ and the trapping of m- by 4He++ following the fusion process and also the regeneration of m- from the (m- 4He++) system. All of these investigations are expected to provide valuable information about processes for improving the economic efficiency of muon catalyzed fusion, (XIV) Study of Structures of Silicon - Rare Earth and SiGe - Rare Earth Systems – In view of the importance of these systems especially with Er as the rare earth impurity in optoelectronics and optocommunications, we are working on features pertinent for these uses of the Er-Si systems. The features under investigation are the locations of Er ions in the presence or absence of co-dopants of the second period, the nature of the electron distribution associated with the Er ions, the nature of the co-dopant environment associated with the Er ions, the nature of the excitation processes with the luminescence associated with the Er ions and the mechanisms responsible for the enhancement of photoluminescence by the presence of co-dopants. The natures of these features for Si-Ge host as compared to Si are also under investigation, (XV) Studies of Electronic Structures and Associated Properties of Nano-Structured Materials – We have worked in the past on C60 fullerenes especially with respect to attachment of hydrogen (muonium) to them and also on the symmetry of nanostructured ZnO systems and their associated 67Zn nuclear quadrupole interactions. Further investigations on these systems and related systems are planned, including carbon nanotubes and the influence of dopants on them as well as multiple quantum well systems related to the Si-Er and SiGe-Er systems being studied under item (n), (XVI) Electronic Structures of Elementary Chalcogens and Glass Transitions in Chalcogen Systems – We are interested in understanding the factors that influence transitions of selenium and tellurium to glassy state especially through incorporation of impurity atoms into the chains and rings in the system. We have in the past investigated the electronic structures of the chains in the rhombohedral lattice in selenium and tellurium by a band structure method and analyzed a number of their properties including the nuclear quadrupole interactions in these systems. We have also used the semi-empirical self-consistent charge Extended Hückel procedure to study the nuclear quadrupole interaction properties in the chains in the rhombohedral structure and rings in the monoclinic lattice. We are currently carrying out electronic structure investigations using the first-principles Hartree-Fock cluster procedure to make comparisons of the calculated nuclear quadrupole interaction parameters with experiment. The Hartree-Fock cluster procedure is well suited to the study of electronic structures associated with impurities which will be very helpful in our planned investigation of bonding energies of antimony, lead and tin impurities in rings and chains of selenium-tellurium alloys. The results of such investigations will be utilized for understanding the available experimental results on the changes in glass transition temperatures for selenium-tellurium alloys under the influence of the impurities.
Past and Present Ph.D. Students and Post-Doctoral Research Associates: Forty-Nine (49) graduate students have received their Ph.D. degrees working under my guidance, twenty-eight (28) in the fields of condensed matter and materials science, twelve (12) in atomic physics, two (2) in molecular physics and seven (7) in biophysics.
Four (4) other graduate students are currently working on their Ph.D. thesis with me, two in both condensed matter and materials science, one only in biophysics and one only in materials science.
The positions that my past Ph.D. students and post-doctoral research associates are currently holding in the USA and abroad are listed under item #9 in my more detailed bio-data on this web-site.
Past and Current International Collaborations: My research group at the Department of Physics at SUNY Albany has had extensive interactions with a number of corresponding groups in other countries over the past twenty-seven years with both experimental research groups as well as theoretical groups in atomic physics, condensed matter and materials physics and biophysics, some of them with support from US National Science Foundation (NSF), North Atlantic Treaty Organization (NATO), US Office of Naval Research (ONR) and Research Organizations in Germany and Japan. These have included research groups in:
Institut für Physikalische Chemie in Technische Hochschule in Darmstadt, Germany [Supported first by US Senior Scientist Award from Alexander von Humboldt Stiftung, Germany and later by Deutsche Forschungsgemeinschaft, Germany and North Atlantic Treaty Organization]
Institut für Atomphysik, Johannes Gutenberg Universität Mainz, Germany [Supported by Senior Scientist Award from Alexander von Humboldt Stiftung, Germany]
Technische Natuurkunde Department in Technische Universiteit Delft in Delft, Netherlands
Institutul Di Fisica in University of Bucharest in Bucharest, Romania [Supported by NSF and Romanian Institute of Science and Technology]
Instituut voor Kern En Strahlingsfysika, Katholieke Universiteit Leuven, Leuven, Belgium
RISO National Laboratory, Roskilde University, Roskilde, Denmark
Institute of Physics, University of Århus, Århus, Denmark [Nordita Fellowship]
Institut für Physik, Technische Universität München in München, Germany
Institut für Physik, Universität Konstanz in Konstanz, Germany
Physikalisches Institut der Universität Erlangen-Nürnberg, Erlangen, Germany
Fysiska Institutionen, Materialfysik, Uppsala Universitet, Uppsala, Sweden
Fakultät für Physik und Astronomie, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
Fachbereich Physik der Universität Marburg, Marburg, Germany
Department of Physics at Indian Institute of Technology, Madras in Chennai (Madras), India [Supported by US-India Collaboration Program, ONR]
Institute of Physics, Bhubaneswar, Orissa, India [Supported by US-India Collaboration Program, ONR]
School of Physics, University of Hyderabad, Hyderabad, India [Supported by US-India Collaboration Program, ONR]
Department of Physics, Yeung Nam University, Taegu, South Korea
Department of Physics, University of Durban-Westville, Durban, South Africa
Faculty of Science, University of Tokyo, Bunkyo-ku, Tokyo, Japan [Supported by Yamada Science Foundation Award from Japan]
Muon Science Laboratory, Institute of Physical and Chemical Research (RIKEN), Wako-shi, Saitama, Japan [Supported by Muon Science Laboratory, RIKEN, first through Eminent Science Award from RIKEN and later through other support funds for Visiting Scientists]
Meson Science Laboratory at Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba-Shi, Ibaraki, Japan [Supported by Visiting Senior Scientist Award from Ministry of Education, Research, Sports and Culture (Monbusho) Japan]
Central Departments of Physics and Computer Science, Tribhuvan University, Kirtipur, Kathmandu, Nepal [Supported by NSF under US-Nepal Collaboration Program and University Grants Commission, Nepal], jointly with an experimental group in Department of Physics, University of Central Florida, Orlando, Florida
Institut für Physik, Technische Universität Braunschweig, Braunschweig, Germany.
Apart from the benefits to the various research areas in the fields of Atomic Physics, Materials Science, Condensed Matter Physics and Biophysics that we have been interacting with International Research Groups (especially in the cases of our interactions with experimental groups where our respective experiences are brought to bear in theory and experiment on the problems we work on jointly as evidenced by our joint publications in the respective areas as listed in the list of publications in the more detailed bio-data) and to the respective Universities or Research Institutes that we have been interacting with, it has been particularly helpful to my Ph.D. students, who have had the opportunity to broaden their training by interacting with the other groups with expertise in areas complementary to theirs. As listed at the end of Section 10 of my detailed bio-data, nineteen of my past students have received their Ph.D. degrees from work on projects where there has been extensive interaction between my research group and other international research groups.
At the present time, we have collaborations in progress with the five international groups listed in items (xv), (xviii), (xxi), (xxii) and (xxiii). All four of my present Ph.D. students are working on areas of common interest to one or more of these five groups.
Publications (Books, Reviews and Journal Articles): I have authored three books (two jointly with one co-author in each case and one by myself), sixteen review articles (either by myself or with others as co-authors) and 396 research articles in leading refereed journals in Physics, Chemistry, Biophysics and Biochemistry, of which 380 are already published or in press and 16 others submitted for publication, involving all areas of my interests in atomic physics, condensed matter physics and material science and biophysics. Please follow this link for a list of the books I have authored co-authored and recent reviews and papers (and a few earlier ones) in my various areas of interest by my research group, collaborators at other centers and myself.
Abstracts Presented at National and International Conferences: A list of Abstracts of papers that my students, collaborators and I have presented at National and International Meetings since 2001 can be found under this link. The Conferences listed are typical of Conferences where we presented papers since the mid 1960`s. In addition to these Conferences we have also presented papers at some other Conferences on topics involving research interests of myself and my group.
<-- Return to Homepage