title: Infrared multiple photon dissociation spectroscopy of potassiated proline.
abstract: The structure of proline in [proline + K]+ has been investigated in the gas phase using high level DFT and MP2 calculations and infrared photo dissociation spectroscopy with a free electron laser (FELIX). The respective FELIX spectrum of [proline + K]+ matches convincingly the calculated spectra of two structurally closely related and nearly iso-energetic zwitterionic salt bridge (SB) structures. An additional unresolved band at approximately 1725 cm(-1) matching with the characteristic CO stretching mode of charge solvation (CS) structures points toward the presence of a minor population of these conformers of proline in [proline + K]+. However, theory predicts a significant energy gap of 18.9 kJ mol(-1) (B3LYP/6-311++G(2d,2p)) or 15.6 kJ mol(-1) (MP2) between the lowest CS conformer of proline and the clearly favored SB structure.
authors.forename: Miriam K
authors.initials: MK
authors.lastname: Drayss
authors.forename: Dirk
authors.initials: D
authors.lastname: Blunk
authors.forename: Jos
authors.initials: J
authors.lastname: Oomens
authors.forename: Mathias
authors.initials: M
authors.lastname: Schäfer
mesh_terms: D017785:Photons; D011188:Potassium / Q000737:chemistry*; D011392:Proline / Q000737:chemistry*; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared
chemical_list: D011392:Proline; D011188:Potassium