Ellis and Randy are looking at a molecular absorption spectrum. The spectral lines appear to fall into two groups with a gap in the middle. Ellis says that this must be an absorption spectrum for transitions between the v = 0 and v = 1 vibrational states of a diatomic molecule. Randy says the gap in the middle must occur because a ΔJ = 0 transition is forbidden. Which one, if either, is correct, and why?
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Ellis, because rotational levels are separated by greater energy differences than vibrational levels.
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Randy, because rotational levels are separated by greater energy differences than vibrational levels.
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Ellis, because the ΔJ = 0 transition is the most prominent spectral line in transitions between vibrational levels.
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Neither, because rotational levels are separated by greater energies that vibrational levels and ΔJ = 0 transitions are not forbidden.
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Both, because vibrational levels are separated by greater energy differences than rotational levels and ΔJ = 0 transitions are forbidden.