Vibrations of Free Molecules - 2. Forms of Vibration of the Methyl Group in Propene

72 views

Formal Metadata

Title
Vibrations of Free Molecules - 2. Forms of Vibration of the Methyl Group in Propene
Alternative Title
Schwingungen freier Moleküle - 2. Schwingungsformen der Methylgruppe in Propen
Author
Schrader, Bernhard
Schneider, Richard
License
CC Attribution - NonCommercial - NoDerivatives 3.0 Germany:
You are free to use, copy, distribute and transmit the work or content in unchanged form for any legal and non-commercial purpose as long as the work is attributed to the author in the manner specified by the author or licensor.
DOI
IWF Signature
C 1210
Publisher
IWF (Göttingen)
Release Date
1976
Language
English
Producer
IWF
Production Year
1975

Technical Metadata

IWF Technical Data
Film, 16 mm, LT, 71 m ; F, 6 1/2 min

Content Metadata

Subject Area
Abstract
The movement of the atoms during the more important normal vibrations of propene are shown in perspective representation: the stretching vibrations of the C=C double bond and the stretching and bending vibrations of the CH[3]-group. The in-phase and out-of-phase movements as well as the concept of characteristic vibrations become clear in the process.
Keywords
molecular structure
oscillations / in molecules
Propene Chemical formula Molecule Computer animation Molecule Ethylene
Propene Molecule Raman scattering Computer animation Infrarotspektroskopie Chemical bond Methylgruppe
Gemstone Setzen <Verfahrenstechnik> Raman scattering Computer animation Doppelbindung Molecular geometry Methylgruppe
Computer animation Functional group Methylgruppe Motion (physics)
Raman scattering Computer animation Deformation (mechanics) Infrarotspektroskopie Chemical bond Atomic number Methylgruppe
Insulin shock therapy Computer animation Infrarotspektroskopie
Raman scattering Computer animation Functional group Infrarotspektroskopie Motion (physics)
Computer animation Functional group Infrarotspektroskopie Raman spectroscopy
Molecule Left-wing politics Computer animation Torsio Motion (physics)
Computer animation
Liquefied natural gas Nitrosamine
Vibrations of Free Molecules - Vibration of the Methyl Group in Propene This is the formula of a more complicated molecule: propene. Since the molecule contains nine atoms, 21 normal vibrations are possible. In each
propene molecule the nearest hydrogen atom of the methyl group lies in the plane of the molecule.The C= C double
bond stretching vibration is infrared- and Ramanactive.You may observe the
large variations in the length
of the C= C double bond and also the simultaneous changes in many bond angles.The methyl group has nine possible vibrations: There are three stretching vibrations, three scissors vibrations, and two rocking vibrations. Two of each type of vibrations are degenerate; that is, they have the same frequency. There is also one twisting vibration.At about 3000 wave numbers we find a symmetric and two degenerate
stretching vibrations of the methyl
group. Let us now look at one of the degenerate stretching vibrations. The motions of the CH-bonds nearest to and farthest from us are outof-phase.The
CH 3 scissors vibrations occur at about 1400 wave numbers. We
shall first observe the symmetric scissors vibration.You can clearly see that the length of the neighbouring C-C bond also vary. All the atoms move a little.This is one of the degenerate deformations of the methyl group.While the angle between the two CH-bonds pointing away from
us increases, the angle with the CH--bond pointing towards us
decreases and vice versa. The rocking vibration ist only visible in the infrared spectrum.Apart from
the rocking motion of the CH 3 group, you can sec that the CH 2 group on
the left moves in the
opposite direction. The intensity of
the torsional vibration of the CH 3 group is extremely small in the infrared and the Raman spectrum.You can see clearly
that the left und right
hand parts of the molecule execute a torsional motion in opposite directions.
Loading...
Feedback

Timings

  433 ms - page object

Version

AV-Portal 3.9.1 (0da88e96ae8dbbf323d1005dc12c7aa41dfc5a31)