Conformational dynamics in a dipeptide after single-mode vibrational excitation.
The dynamics of conformational isomerization are explored in a methyl-capped dipeptide, N-acetyl-tryptophan methyl amide (NATMA), using infrared-ultraviolet (IR-UV) hole-filling and IR-induced population transfer spectroscopies. IR radiation selectively excites individual NH stretch vibrational fundamentals of single conformations of the molecule in the early portions of a gas-phase expansion, and then this excited population is collisionally recooled into its conformational minima for subsequent conformation-specific detection. Efficient isomerization is induced by the IR excitation that redistributes population between the same conformations that have population in the absence of IR excitation. The quantum yields for transfer of the population into the various conformational minima depend uniquely on which conformation is excited and on which NH stretch vibration is excited within a given conformation.
Dian
Brian C
BC
Department of Chemistry, Purdue University, West Lafayette, IN 47907-1393, USA.
Longarte
Asier
A
Zwier
Timothy S
TS
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004151:Dipeptides / Q000737:chemistry*; D006860:Hydrogen Bonding; D007259:Infrared Rays; D007536:Isomerism; D007834:Lasers; D008968:Molecular Conformation; D011487:Protein Conformation; D013057:Spectrum Analysis; D013696:Temperature; D013816:Thermodynamics; D014364:Tryptophan / Q000031:analogs & derivatives* / Q000737:chemistry*; D014466:Ultraviolet Rays; D014732:Vibration
D004151:Dipeptides; C071046:N-acetyltryptophan methylamide; D014364:Tryptophan