Band
Title
8257.0 cm-1: ν12+3ν4 of 12CH4 in natural CH4 - phase I
Type
absorption
Assignments summary
Assignment Symmetry Mode Specie(s) Molecule/Atom Bond Multiplicity Degeneracy Contribution Resonance
ν12+3ν4 combination vibration 12CH4 CH4 12C-1H
12C-1H
12C-1H
unknown
Characteristics summary
Peak position
(cm-1)
Center position
(cm-1)
Width
(cm-1)
Shape Asymmetry factor Peak intensity
(cm-1)
Peak intensity relative Peak strength Integrated intensity
(cm-2)
Integrated intensity relative Integrated strength Temperature
(K)
Pressure
(bar)
8257 ± 2 - - asymmetric 0.0885 ± 0.002 1.106e-05 vvw 30.0
8259 ± 5 - - shoulder 90.0 0.117
Label
ν12+3ν4
Category
combination vibration

Evaluation

Level
fully assigned
Evaluation
validated
# Multiplicity type Degeneracy Other band
1 unknown

Vibration modes

Label (type)
ν1 (stretching sym.)       Bond: 12C-1H
ν2 (deformation)       Bond: 12C-1H
4 (deformation)       Bond: 12C-1H
Texture
crystal

Temperature

Temperature
30.0 ± 1.0 K
Formation temperature
90.7 K
Temperature max
90.7 K
Method #1
spectrum measurement
Overlap
slightly blended
Peak
8257 ± 2 cm-1 (peak)
Evaluation
validated
Quality
B
Shape
asymmetric
Evaluation
undefined
Method
peak intensity
Absorption coefficient
0.0885 ± 0.002 cm-1
Relative intensity
1.106e-05 ± 2.5e-07
Strength
very very weak (vvw)
Evaluation
validated
Quality
B
Texture
crystal

Temperature

Temperature
90.0 ± 1.0 K
Formation temperature
90.7 K
Temperature max
90.7 K

Pressure

Pressure
0.117 bar
Comments
Vapor pressure
Method #1
spectrum measurement
Overlap
shoulder-tail
Peak
8259 ± 5 cm-1 (other)
Evaluation
undefined
Quality
C
Shape
shoulder
Comments
weak shoulder in the wing of the 8311 cm-1 band