... plane of polarization of incoming light. The
molecules of these materials (crystals and com-
pounds) have asymmetric molecular structures.
Themoleculescanexistinleft-andright-handed
forms. Particular ... density of oc-
cupation in energy. The term f (ε)g(ε) plotted
as a function of energy, ε, represents the total
number of particles in the system.
occupationnumber Thenumberof...
... theorem is of great
value in understanding magnetic ions in crystals.
degeneracy, lifting of, or removal of Slight
inequality of energy of a group of quantum states
due to the presence of a perturbation, ... in particle-antiparticle pairs,
bosons can be created and destroyed singly.
bounce frequency The average frequency
of oscillation of a particle trapped in a magnetic...
... of detailed balance In equilib-
rium, the power radiated and absorbed by a body
must be equal for any particular element of area
of the body, for any particular direction of po-
larization, and ... is a linear function of its fre-
quency was the origin of the understanding, due
to A. Einstein, of light as consisting of quanta
of energy E = hν, where ν is the frequency...
... conservation
of energy and momentum.
density of modes The number of modes of
the radiation field in an energy range dE. The
density of modes is a function of the boundary
conditions ofthe spaceunder ... single point particle
in three-dimensional space has three degrees of
freedom; a system of N point particles has 3N
degrees of freedom.
De Haas–Van Alphan effect In 193...
... in
the study of Brownian motion in 190 5 and 190 6,
the concept was significantly extended by H.
Nyquist ( 192 8), L. Onsager ( 193 1), H.B. Callen
and T.A. Welton ( 195 1), and R. Kubo ( 195 7).
See also ... shift).
energy spectrum The set of energy eigen-
states of a physical system. The set of possible
outcomes of a measurement of the energy; also
known as the set of...
... the number of particles in a state of
energy E
s
.
grand unification Physics attempts to ex-
plain natural phenomenon in terms of a set of
fundamental axioms. It is the general goal of
physics to ... wave-
length, g
1
and g
2
are degeneracies of lower and
excited states, N
1
and N
2
are the number of
atoms in the lower and excited states, ν and ν
o
are field and...
... are made of heterojunctions. A het-
erojunction is made of layers of two different
types of materials which are doped by p and n
types of atoms. For example, layers of n and
p type GaAs and AlGaAs ... exists.
impurity band An energy level caused by
the presence of impurity atoms.
incident energy The energy of the incoming
particle in a collision process.
incident fl...
... in
a flow field.
kinetic energy A form of energy associated
with motion. Every moving particle has kinetic
energy. The kinetic energy of a non-relativistic
particle with mass m and speed v is equal ... =
m
1
m
2
m
1
+m
2
is the reduced mass for particles
of mass m
1
and m
2
, and r = r
1
− r
2
are the
relative position vectors of particles 1 and 2.
Suitable sets of cent...
... reduction of the tem-
perature of atoms in the gas or bulk phase by
means of laser radiation. Most often the cool-
ing is associated with a reduction in the speed
of the atoms and a narrowing of their ... descriptionof the distributionof speeds
present in a collection ofgasmolecules. A com-
bination ofthe statisticalargumentsproposed by
James Clerk Maxwell (1831–18 79) and Ludwi...