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avkr
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The selection rule for rotational spectra ##ΔJ = ±1##. Is it always true for the emission part of rotation spectra ##ΔJ = -1## and how?
Rotational spectra is a technique used in the field of spectroscopy to study the rotational motion of molecules. It involves measuring the absorption or emission of electromagnetic radiation by a molecule as it rotates.
The ΔJ selection rule states that rotational transitions between energy levels with a change in rotational quantum number, J, of ±1 are allowed in rotational spectra. Transitions with a change in J of 0 or ±2 are forbidden.
The ΔJ selection rule determines the spacing between rotational energy levels and therefore the spacing between spectral lines. This results in the characteristic P and R branch lines observed in rotational spectra.
The emission part in rotational spectra refers to the portion of the spectrum where the molecule is emitting electromagnetic radiation. This occurs when the molecule transitions from a higher energy level to a lower energy level, releasing energy in the form of radiation.
Rotational spectra is used in chemistry and physics to study the structure and dynamics of molecules. It can provide information about molecular geometry, bond lengths, and bond angles. It is also used in the identification and analysis of molecules in various fields such as astrophysics, atmospheric science, and environmental science.