fied as a university lecturer in 1910 after having
obtained a Ph.D. in physics in 1908 there.
In 1911 he went on to become professor of theo-
retical physics at Zurich University for two years and
then returned to the Netherlands in 1912 as appointed
professor of theoretical physics at Utrecht University. In
1913 he married Mathilde Alberer, with whom he had
a son and a daughter. His son (Peter P. Debye) became
a physicist and collaborated with Debye on some of his
research. The following year, he moved to the Univer-
sity of Göttingen, heading the theoretical department of
the Physical Institute. In 1915 he became editor of
Physikalische Zeitschrift(until 1940). He became direc-
tor of the entire Physical Institute and lectured on
experimental physics until 1920.
Debye returned to Zurich in 1920 as professor of
physics and principal of the Eidgenössische Technische
Hochschule, and seven years later he held the same
post at Leipzig. From 1934 to 1939 he was director of
the Max Planck Institute of the Kaiser Wilhelm Insti-
tute for Physics in Berlin-Dahlem and professor of
physics at the University of Berlin. During this period
he was awarded the 1936 Nobel Prize in chemistry
“for his contributions to our knowledge of molecular
structure through his investigations on dipole moments
and on the diffraction of X-rays and electrons in
gases.”
In 1940 he became professor of chemistry and
principal of the chemistry department of Cornell Uni-
versity, in Ithaca, New York, and he became an Ameri-
can citizen in 1946.
In 1952 he resigned his post as head of the chem-
istry department at Cornell University and became
emeritus professor of chemistry there.
Much of his later work at Cornell dealt with light-
scattering techniques (derived from his X-ray scattering
work of years earlier) to determine the size and molecu-
lar weight of polymer molecules. This interest was a
carryover from his work during World War II on syn-
thetic rubber and extended to proteins and other
macromolecules.
During his career Debye was awarded the Rumford
Medal of the Royal Society, London, the Franklin and
Faraday Medals, the Lorentz Medal of the Royal
Netherlands Academy, the Max Planck Medal (1950),
the Willard Gibbs Medal (1949), the Nichols Medal
(1961), the Kendall Award (Miami, 1957), and the
Priestley Medal of the American Chemical Society
(1963). He was appointed Kommandeur des Ordens by
Leopold II in 1956 and died of a heart attack on
November 2, 1966.decant To draw off the upper layer of liquid after the
heaviest material, which can be a solid or another liq-
uid, has settled to the bottom.decay constant(disintegration constant) A constant
that expresses the probability that an atom or molecule
of a chemical will decay in a given time interval.decomposers A trophic level or group of organisms
such as fungi, bacteria, insects, and others that, as a
group, digest or break down organic matter, such as
dead animals, plants, or other organic waste, by ingest-
ing the matter, secreting enzymes or other chemicals,
and turning it into simpler inorganic molecules or com-
pounds that are released back into the environment.decomposition The breakdown of matter by bacte-
ria and fungi. It changes the chemical makeup and
physical appearance of materials.decomposition, chemical The breakdown of a sin-
gle entity (normal molecule, reaction INTERMEDIATE,
etc.) into two or more fragments.de-electronation SeeOXIDATION.degree A unit of angular measure, often represented
by the symbol °. The circumference of a circle contains
360 degrees. When applied to the roughly spherical
shape of the Earth for geographic and cartographic
purposes, degrees are each divided into 60 min. Also
refers to temperature, as in degrees Celsius or degrees
Fahrenheit, usually represented by the symbol °.degenerate Describing different quantum states that
have the same energy.degenerate 71