Department of Chemistry

School of Natural Sciences and Mathematics

Richard A. Caldwell, Ph.D.

Organic Photochemistry

Research Group

Caldwell Homepage


B.S., Massachusetts Institute of Technology (1961): Chemistry
Ph.D., University of California, Berkeley (1965): Organic Chemistry
Postdoctoral Associate, California Institute of Technology (1964-65)
Advisor: G. S. Hammond

Research Description

A physical organic chemist studying photochemical mechanisms, Dr. Caldwell has centered his work on the observation of reactive intermediates and determination of their chemical and physical properties. His best known early work established the involvement of exciplexes as obligatory intermediates in photochemical reactions. More recent work emphasizes (1) transient spectroscopy and theoretical studies of olefin triplets and triplet biradicals to understand the factors which cause intersystem crossing; (2) studies of reactivity in singlet and triplet state photocycloaddi-tions to understand the fundamental origins of such photoreactivity; (3) studies of highly strained, transient ground state species such as trans- cyclohexenes and -heptenes.

Selected Publications

Caldwell, R.A.; Zhou, L. "Are Perpendicular Alkene Triplets Just 1,2- Biradicals? Studies with the Cyclopropylcarbinyl Clock", J. Am. Chem. Soc. (1994) 116: 2271-2275.

Caldwell, R.A.; Strickland, D. "Thermochemistry of Strained Cycloalkenes: Experimental and Computational Studies", J. Phys. Chem. (1993) 97: 13394-13402.

Caldwell, R.A. "Laser Flash Photolysis Studies of Intersystem Crossing in Biradicals and Alkene Triplets”, in: Platz, M. (ed.) "Kinetics and Spectroscopy of Carbenes and Biradicals" Plenum Publishing: New York; pp 77-116 (1990).

  • Updated: September 8, 2005