
Robert Ghormley Parr (September 22, 1921 – March 27, 2017) was an American
theoretical chemist
Theoretical chemistry is the branch of chemistry which develops theoretical generalizations that are part of the theoretical arsenal of modern chemistry: for example, the concepts of chemical bonding, chemical reaction, valence, the surface o ...
who was a professor of chemistry at the
University of North Carolina at Chapel Hill
The University of North Carolina at Chapel Hill (UNC, UNC–Chapel Hill, or simply Carolina) is a public university, public research university in Chapel Hill, North Carolina, United States. Chartered in 1789, the university first began enrolli ...
.
Career
Parr received an A. B.
degree ''magna cum laude'' from
Brown University
Brown University is a Private university, private Ivy League research university in Providence, Rhode Island, United States. It is the List of colonial colleges, seventh-oldest institution of higher education in the US, founded in 1764 as the ' ...
in 1942, and then entered the
University of Minnesota
The University of Minnesota Twin Cities (historically known as University of Minnesota) is a public university, public Land-grant university, land-grant research university in the Minneapolis–Saint Paul, Twin Cities of Minneapolis and Saint ...
, receiving a Ph.D. in
physical chemistry
Physical chemistry is the study of macroscopic and microscopic phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical mech ...
in 1947. He joined the faculty at Minnesota upon receiving his Ph.D. and remained there one year. In 1948 he moved to the
Carnegie Institute of Technology
Carnegie Mellon University (CMU) is a private research university in Pittsburgh, Pennsylvania, United States. The institution was established in 1900 by Andrew Carnegie as the Carnegie Technical Schools. In 1912, it became the Carnegie Institu ...
(now
Carnegie Mellon University
Carnegie Mellon University (CMU) is a private research university in Pittsburgh, Pennsylvania, United States. The institution was established in 1900 by Andrew Carnegie as the Carnegie Technical Schools. In 1912, it became the Carnegie Institu ...
) in
Pittsburgh
Pittsburgh ( ) is a city in Allegheny County, Pennsylvania, United States, and its county seat. It is the List of municipalities in Pennsylvania#Municipalities, second-most populous city in Pennsylvania (after Philadelphia) and the List of Un ...
,
Pennsylvania
Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...
, becoming a full professor in 1957. In 1962 he moved to
Johns Hopkins University
The Johns Hopkins University (often abbreviated as Johns Hopkins, Hopkins, or JHU) is a private university, private research university in Baltimore, Maryland, United States. Founded in 1876 based on the European research institution model, J ...
in
Baltimore, Maryland
Baltimore is the List of municipalities in Maryland, most populous city in the U.S. state of Maryland. With a population of 585,708 at the 2020 United States census, 2020 census and estimated at 568,271 in 2024, it is the List of United States ...
, and in 1974 to the
University of North Carolina at Chapel Hill
The University of North Carolina at Chapel Hill (UNC, UNC–Chapel Hill, or simply Carolina) is a public university, public research university in Chapel Hill, North Carolina, United States. Chartered in 1789, the university first began enrolli ...
, where he received appointment to an endowed professorship in 1990 and where he last taught.
Achievements and awards
Working with
DuPont
Dupont, DuPont, Du Pont, duPont, or du Pont may refer to:
People
* Dupont (surname) Dupont, also spelled as DuPont, duPont, Du Pont, or du Pont is a French surname meaning "of the bridge", historically indicating that the holder of the surname re ...
chemist
Rudolph Pariser
Rudolph Israel Pariser (December 8, 1923 – February 2, 2021) was an American physical and polymer chemist.
Biography
Rudolph Israel Pariser was born in Harbin, China to merchant parents, Ludwig Jacob Pariser and Lia Rubinstein. He attended t ...
, Parr developed a method of computing approximate
molecular orbital
In chemistry, a molecular orbital is a mathematical function describing the location and wave-like behavior of an electron in a molecule. This function can be used to calculate chemical and physical properties such as the probability of finding ...
s for
pi electron
In chemistry, pi bonds (π bonds) are covalent chemical bonds, in each of which two lobes of an orbital on one atom overlap with two lobes of an orbital on another atom, and in which this overlap occurs laterally. Each of these atomic orbitals ...
systems, published in 1953. Since an identical procedure was derived by
John A. Pople the same year, it is generally referred to as the
Pariser–Parr–Pople method
In molecular physics, the Pariser–Parr–Pople method applies semi-empirical quantum mechanical methods to the quantitative prediction of electronic structures and spectra, in molecules of interest in the field of organic chemistry. Previous meth ...
or PPP method. The PPP method differed from existing structural chemistry thinking (which advocated ''maximum overlap principle'') by advancing the concept of ''zero differential overlap approximation''.
By 1978 Parr had realized that
density functional theory
Density functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (or nuclear structure) (principally the ground state) of many-body ...
(DFT) would be extremely useful in quantitative calculations of chemical and biological systems, especially those with high molecular weights. In 1988 Parr,
Weitao Yang
Weitao Yang (; born March 31, 1961) is a Chinese-born American chemist who is the Philip Handler Professor of Chemistry at Duke University. His main contributions to chemistry include density functional theory development, and its applications t ...
and Chengteh Lee produced an improved DFT method which could approximate the correlation energy of systems. The LYP (for Lee–Yang–Parr) functional theory is now one of the most cited papers in the chemical literature.
In 1963 Parr published ''Quantum Theory of Molecular Electronic Structure'', one of the first books to apply quantum theory to chemical systems.
In 1989 he and Yang published ''Density Functional Theory of Atoms and Molecules'', now considered the basic textbook on DFT.
Awards and honors
*Member of the
International Academy of Quantum Molecular Science
The International Academy of Quantum Molecular Science (IAQMS) is an international scientific learned society covering all applications of quantum theory to chemistry and chemical physics. It was created in Menton in 1967. The founding members we ...
[
*1967 - Co-founded (with 4 others) the ]International Academy of Quantum Molecular Science
The International Academy of Quantum Molecular Science (IAQMS) is an international scientific learned society covering all applications of quantum theory to chemistry and chemical physics. It was created in Menton in 1967. The founding members we ...
[
*1994 - Winner of ]American Chemical Society
The American Chemical Society (ACS) is a scientific society based in the United States that supports scientific inquiry in the field of chemistry. Founded in 1876 at New York University, the ACS currently has more than 155,000 members at all ...
's Irving Langmuir Award The Irving Langmuir Prize in Chemical Physics is awarded annually, in even years by the American Chemical Society and in odd years by the American Physical Society. The award is meant to recognize and encourage outstanding interdisciplinary research ...
in Chemical Physics
*2004 - winner of United States National Academy of Sciences
The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...
Award in Chemical Sciences[
*2009 - winner of American Chemical Society's Award in Theoretical Chemistry]
References
{{DEFAULTSORT:Parr, Robert
1921 births
2017 deaths
Brown University alumni
University of Minnesota alumni
American physical chemists
American theoretical chemists
Carnegie Mellon University faculty
Members of the United States National Academy of Sciences
Members of the International Academy of Quantum Molecular Science
Foreign fellows of the Indian National Science Academy
American computational chemists
Fellows of the American Physical Society