Where is the hidden intramolecular H-bonding vibrational signal in the proline matrix IR spectrum?

The assignment of the hydrogen bonded O–H stretch vibration in the proline matrix IR spectrum has sparked controversy. Employing constrained nuclear electronic orbital methods, we provide a clear assignment that the vibrational frequency drops to near 3000 cm−1 as a result of the interplay between electronic effects, nuclear quantum effects, and matrix effects. [ABSTRACT FROM AUTHOR]