Takeshi Oka Professor Emeritus of Chemistry and Astronomy & As

Born Tokyo, Japan, 1932.
of Tokyo, B.S., 1955; Ph.D., 1960.
Fellow, JSPS, University of Tokyo, 1960-1963.
Herzberg Institute of Astrophysics, 1963-1981.
The University of Chicago, Professor, 1981-.
Joint Appointment in the Department of Astronomy and Astrohysics and the Enrico Fermi Institute.

Accolades

Fellow, American Academy of Arts and Sciences
Fellow, American Physical Society
Fellow, Optical Society of America
Fellow, Royal Society of London
Fellow, Royal Society of Canada
2004 Davy Medal of the Royal Society.
2004 Wei Lun Visiting Professorship.
2004 Honorary DSc from the University College London.
2004 Norman MacLean Faculty Award.
2003 Earl W. McDaniel Lecture Georgia Institute of Technology.
2002 E. B. Wilson Award of ACS.
2001 Honoris caua, University of Waterloo.
2000 George Pimentel Memorial Lecture, University of California, Berkeley.
1998 Ellis R. Lippincott Award, Optical Society of America.
1998 Medaili Jana Marca Marci.
1997 William F. Meggers Award, Optical Society of America.
1997 Distinguished JILA Visitor.
1995 Golden Jubilee Lecture, Tata Institute of Fundamental Research.
1992 Special Issue, Journal of Molecular Spectroscopy, Vol. 153.
1992 Lecturer, International School of Physics, "Enrico Fermi".
1992 Lord Lecturer, Massachusetts Institute of Technology.
1990 Burlington Northern Achievement Award.
1989 McDowell Lecturer, University of British Columbia.
1985-1986 Chancellor's Distinguished Lecturer, University of California, Berkeley.
1982 Earle K. Plyler Prize of APS.
1981-1982 Centenary Lecturer, Royal Society.
1973 Steacie Prize.

OFFICE: GHJ 006 , 5735 S Ellis Ave, Chicago, IL 60637

PHONE: (773)702-7070

FAX: (773)702-0805

E-MAIL: t-oka@uchicago.edu

WEB: http://fermi.uchicago.edu/

RESEARCH INTERESTS:

Students in the Oka group use a variety of infrared, nearinfrared and visible laser radiation sources to conduct high-resolution high-sensitivity spectroscopy of molecular ions in laboratory plasmas. Our studies are closely related to astronomy, and we also observe the absorption and emission spectra of these ions in astronomical objects. The unifying theme of our studies is the understanding of the quantum mechanics and dynamics of fundamental molecular ions and their behavior in astronomical objects.


Molecular Ions in Laboratory Plasmas
We produces molecular ions in plasmas by applying an electric field onto low pressure gas cells. In these discharges, the ions are produced in small concentrations and we detect them using very high sensitivity laser spectroscopy. In collaboration with theorists we study the intramolecular dynamics of molecular ions , which are often unusual. Current projects include the study of C3H3+, the simplest Hückel's aromatic, near-infrared electronic spectrum of CH2+ between the Renner-Teller split states, and low resolution cavity ringdown spectroscopy of C60+.


Molecular Ions in Astronomical Plasmas
The on going unification of chemistry and astronomy has revealed that "molecular clouds" are the birthplace of stars and that the chemical evolution of the clouds is a crucial step in star formation. The idea has emerged in these studies that molecular ion H3+ plays pivotal roles in such processes. Since our discovery in 1980 of the laboratory infrared spectrum of H3+, we have been actively engaged in a search for this ion in interstellar space. This search finally paid off in 1996 with the detection of H3+ in two molecular clouds. Further work has demonstrated the abundance of H3+ not only in more molecular clouds where its presence was predicted but also unexpectedly in diffuse clouds. We have now established that H3+ is ubiquitous in many astronomical objects and the understanding of its chemistry is crucial in interstellar chemistry. Currently we are studying very abundant H3+ near the Galactic center. The studies of H3+ spearheads the field but most other molecular ions studied in our lab will also be detected in space. So far our laboratory studies have led to the detection of ions such as HCNH+ and H3O+ in molecular clouds.


Selected References

Near-infrared electronic spectrum of CH2+. J. Chem. Phys.,, 121, 11527 (2004).

High-resolution spectroscopy of the 22Πu←Χ4Σg- forbidden transitions of C2+. J. Chem. Phys., 121, 6290 (2004)

Atomic and molecular emission lines from the Red Rectangle. Astrophys. J., 615, 947 (2004)

The non-thermal rotational distribution of H3+. Astrophys. J., 613, 349 (2004).

Nuclear spin selection rules in chemical reactions by angular momentum algebra. J. Mol. Spectroscc., 228, 635 (2004).

Near-infrared spectroscopy of H3+ above the barrier to linearity. J. Chem. Phys., 118, 10890 (2003).

Observations of C3 in translucent sightlines. Astrophys. J., 582, 823 (2003).

Absorption line survey of H3+ toward the Galactic center sources I. GCS 3-2 and GC IRS2. Publ. Astron. Soc. Japan,, 54, 951 (2002).

Observation of H3+ in the diffuse interstellar medium. Astrophys. J., 567, 391 (2002).

Sharp Spectral Lines Observed in γ-Ray Ionized Parahydrogen Crystals. Phys. Rev. Lett. 86, 4795 (2001).

CH5+:The Infrared Spectrum Observed. Science, 284, 135 (1999).