Royal Society of Chemistry, Chemical Science, 8(11), p. 2112-2120, 2020
DOI: 10.1039/c9sc05717j
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Break down of the Born–Oppenheimer approximation is caused by mixing of electronic and vibrational transitions in the radical cations of some conjugated polymers, resulting in unusually intense vibrational bands known as infrared active vibrations (IRAVs).