Takanobu Ishida

Takanobu Ishida, Professor Emeritus

B.S., 1953
M.S., 1955, Kyoto University
M.S., 1958, New York University
Ph.D., 1964, Massachusetts Institute of Technology






Physical Chemistry: Isotope Effects, Isotope Seperatio, Electrochemistry

Our research interest is best described by considering that it has two focal points, one on chemical and physical effects of stable isotope substitutions in molecules and the second on various aspects of separation of stable isotopes, this field being an application of the first. In the basic studies of isotope effects, we explore differences in the equilibrium and kinetic properties among isotopic molecules and use the information to elucidate intra- and inter-molecular forces, usually assuming the validity of Born-Oppenheimer approximation. The knowledge from the isotope effect studies is also applied to develop efficient processes for enriching stable isotopes, in particular, of the light elements, H, C, N, O, and S.

Separations involving isotopes of the same element are one of the most difficult of all chemical separation processes. These studies involve a perception of new separation principles and implementation of the method into a workable pilot plant which uses affordable feed material and the least amount of energy and gives highest possible separation factor and overall reaction rates. In its course one may get involved with basic isotope effect studies, statistical thermodynamics, molecular dynamics, molecular orbital calculations, molecular spectroscopy, reaction kinetics including catalysis, surface chemistry, chemical engineering designs, and a lot of basic chemistry.

Recently, our interest in heterogeneous electrocatalyses for isotope exchange reactions has led us into the field of chemically modified electrodes and reevaluation of chemistry of nitric oxide. Examples: (a) Development of a hydrophobic catalyst for hydrogen isotope exchange between dihydrogen and liquid water, the catalyst whose activity will be in situ regeneratable. (b) Development of an ultramicro electrochemical probe for a fast, highly sensitive, and reproducible determination of nitric oxide in biological cellular systems. Nitric oxide is produced by mammalian cells as a short-lived intercellular messenger. It participates in blood pressure control, neurotransmission and inflammation. In and around the cells it operates in sub-ppm and often in the ppb concentration levels, and the current knowledge of nitric oxide is often insufficient for the pathological investigations. We are reassessing the properties of this free radical.


  • Research Associate, Brookhaven National Laboratory, 1964-66
  • Research Associate, Belfer Graduate School of Science, Yeshiva University, 1966-68
  • Visiting Associate Professor and Professor, University of Rochester, 1973-79
  • Visiting Scientist, Max Planck Institut fuer Chemie (Otto-Hahn-Institut), Mainz, Germany, 1986


"Enrichment of Isotopes," T. Ishida and Y. Fujii, Chapter 2, pp 41-87, in "Isotope Effects in Chemistry and Biology," A. Kohen and Hans-Heinrich Limbach, Eds, CRC Taylor & Francis, New York, 2005.

"Early History of Chemical Exchange Isotope Enrichments and Lessons We Learn," T. Ishida, Y. Ono, J. Nucl. Sci. Tech,
2005, vol 42 (pages still unknown).

"A Density Functional Theory Study Applied for Carbon and Oxygen Isotope Effects in the System Ni(CO)sub4/CO," Y. Ono, Y. Fujii, T. Ishida, Chem. Phys. Lett. 2004, 390, 421-426.

"A Density Functional Theory Study Apllied for Carbon Isotope Effects in the Non-Aqueous [Cu(CO)]sup+/CO System," Y. Ono, Y. Fujii, S. Nagase, T. Ishida, Chem. Phys. Lett. 2004, 390, 71-78.

"Gas-phase disproportionation of Nitric oxide at elevated pressures, Tsukahara, H., Ishida, T., Todoroki, Y., Hiraoka, M., Mayumi, M., Free Radical Research, 2003, 37, 171-177.

"Gas-phase oxidation and disproportionation of nitric oxide," Tsukahara, H., Ishida, T., Mayumi, M., Methods in Enzymology, Nitric Oxide, 2002, 359, 168-179.

"Isotope effects and isotope separation: A chemist’s view," Ishida, T., 2001, Nucl Sci Tech, 2002, 39, 407-412.

"A porphyrinic sensor for nitrogen monoxide in aqueous solution,’ Tsukahara, H., Ishida, T., Mayumi, M., Kidney and free radicals, 1997, 4, 24.

"Vapor pressure isotope effects in liquid and solid ammonia," King, T. V., Oi, T., Popowicz, A., Heinzinger, K., Ishida, T., Z. Naturforsch., 1989, 44a, 359.

"Additivity of vibrational zero-point energy," Oi, T., Popowicz, A., Ishida, T., J. Phys. Chem., 1986, 90, 3090.

"Nitrogen-15 fractionation by countercurrent exchange between liquid N2O3 –N2O4 mixture and their vapor phases under pressured conditions," Prencipe, M., Spindel, W., Ishida, T., Sep. Sci. Tech., 1985, 20, 489.

"Correlation of zero-point energy with molecular structure and molecular forces. III. Approximation for H/D isotope shifts and linear frequency sum rule," Oi, T., Ishida, T., J. Phys. Chem., 1984, 88, 2057.

"Isotope effect on zero-point energy shift upon condensation. I. Formulation and application to ethylene, methane, and fluoromethanes," Kornblum, Z. C., Ishida, T., J. Chem. Phys., 1978, 69, 1814.

"Medium cluster model for vapor pressure isotope effect," Pollin, J. S., Ishida, T., J. Chem. Phys., 1977, 66, 4433.

"Isotope chemistry and molecular structure. Deviations from the first rule of the mean," Ishida, T., Bigeleisen, J., J. Chem. Phys., 1976, 64, 4775.

"Theoretical analysis of chemical isotope fractionation by the orthogonal polynomial methods,’ Ishida, T., Spindel, W. Bigeleisen, J., Advan. Chem. Ser., 1969, 89, 192.