title: Hydrogen-bonding-induced enhancement of Fermi resonances: a linear IR and nonlinear 2D-IR study of aniline-d5.
abstract: Hydrogen bonding of the amino group of aniline-d5 results in a huge enhancement of the NH2 bending overtone absorption strength, mainly attributed to the Fermi resonance effect. A quantitative analysis is presented, using a hybrid mode representation and encompassing experimental data on aniline with 0, 1, or 2 hydrogen bonds to dimethylsulfoxide (DMSO). Changes in enthalpy, hydrogen-bonding-induced frequency shifts, and the transition dipole moment increase of the local N-H stretching oscillator all demonstrate that the hydrogen bond is strongest in the single hydrogen-bonded complex. Linear IR overtone spectra show that the oscillator strength decreases upon hydrogen bonding for the N-H stretching overtones, which is opposite to the effect on the fundamental N-H stretching transitions. Polarization resolved 2D-IR spectra provide detailed information on the N-H stretching overtone manifold and support the relative orientations of the various IR transitions.
authors.affiliation: Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie , Max Born Strasse 2A, D-12489 Berlin, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Greve
authors.forename: Erik T J
authors.initials: ET
authors.lastname: Nibbering
authors.forename: Henk
authors.initials: H
authors.lastname: Fidder
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D006860:Hydrogen Bonding; D007700:Kinetics; D013055:Spectrophotometry, Infrared
chemical_list: D000814:Aniline Compounds; C023650:aniline; D004121:Dimethyl Sulfoxide