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A phonon is a collective excitation in a periodic, elastic arrangement of atoms or molecules in condensed matter, specifically in solids and some liquids.A type of quasiparticle in physics, [1] a phonon is an excited state in the quantum mechanical quantization of the modes of vibrations for elastic structures of interacting particles.
The term "chiral" in general is used to describe the object that is non-superposable on its mirror image. [18] In chemistry, chirality usually refers to molecules. Two mirror images of a chiral molecule are called enantiomers or optical isomers. Pairs of enantiomers are often designated as "right-", "left-handed" or, if they have no bias ...
A chiral phenomenon is one that is not identical to its mirror image (see the article on mathematical chirality). The spin of a particle may be used to define a handedness, or helicity, for that particle, which, in the case of a massless particle, is the same as chirality. A symmetry transformation between the two is called parity transformation.
Phonons take on both labels such that transverse acoustic and optical phonons are denoted TA and TO, respectively; likewise, longitudinal acoustic and optical phonons are denoted LA and LO. The type of surface phonon can be characterized by its dispersion in relation to the bulk phonon modes of the crystal.
Chiral inversion is the process of conversion of one enantiomer of a chiral molecule to its mirror-image version with no other change in the molecule. [1] [2] [3] [4]Chiral inversion happens depending on various factors (viz. biological-, solvent-, light-, temperature- induced, etc.) and the energy barrier energy barrier associated with the stereogenic element present in the chiral molecule. 2 ...
A planar chiral derivative of ferrocene, used for kinetic resolution of some racemic secondary alcohols [1]. This term is used in chemistry contexts, [2] e.g., for a chiral molecule lacking an asymmetric carbon atom, but possessing two non-coplanar rings that are each dissymmetric and which cannot easily rotate about the chemical bond connecting them: 2,2'-dimethylbiphenyl is perhaps the ...
Hence there is a need to pressurize the entire chromatographic flow path. SFC can differentiate enantiomers and enantiomer from the racemate; (+) from (-) and (±) Chiral capillary electrophoresis (CE) [45] Chiral CE is based largely on separation of enantiomers by complex formation with cyclodextrins which is used as the chiral selector.
In particle physics, chiral symmetry breaking generally refers to the dynamical spontaneous breaking of a chiral symmetry associated with massless fermions. This is usually associated with a gauge theory such as quantum chromodynamics, the quantum field theory of the strong interaction, and it also occurs through the Brout-Englert-Higgs mechanism in the electroweak interactions of the standard ...