Spectral line

Quantum mechanics

Chemical physics

Crystal (programming language)

Materials science

Infrared

Intermolecular interaction

Crystal structure

Phonon

Vibration

Molecule

Computer science

Force constant

Intermolecular force

Hydrogen

Physics

Organic chemistry

Optics

Polyethylene

Molecular physics

Condensed matter physics

Computational chemistry

Crystallography

Chemistry

Programming language

Lattice vibration

Infrared spectroscopy

Hydrogen bond

The Journal of Chemical Physics

Normal frequencies of crystalline polymethylene have been calculated for various phase differences along the c axis of the crystal. Intermolecular hydrogen—hydrogen force constants have been evaluated from the splitting of the spectroscopically active modes. The results of the calculations explain almost satisfactorily the splitting of the progression bands in the infrared spectra of long‐chain n‐paraffins as well as one lattice vibration band in the far‐infrared spectrum of polyethylene.

Crystal Vibrations and Intermolecular Forces of Polymethylene Crystals