Ultrafast vibrational spectroscopy of a degenerate mode of guanidinium chloride.
Nearly degenerate asymmetric stretches with perpendicular transition dipole moments of the deuterated guanidinium cation (DGdm(+)) in D(2)O and D-glycerol/D(2)O mixtures at 1600 cm(-1) were investigated by linear FTIR spectroscopy and polarization dependent femtosecond pump-probe spectroscopy. The vibrational coupling of the asymmetric stretches of guanidinium occurs within 0.5 ps and leads to fast decay of the anisotropy to a level of 0.1. A systematic study of the influence of the coherence transfer on pump-probe signals is given. Following this decay, the anisotropy decays with a time constant of 4.1 ps in D(2)O by rotational diffusion about an axis perpendicular to the DGdm(+) mean plane. The presence of aggregation was demonstrated for concentrations higher than 0.2 M.
Vorobyev
Dmitriy Yu
DY
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Kuo
Chun-Hung
CH
Chen
Jian-Xin
JX
Kuroda
Daniel G
DG
Scott
J Nathan
JN
Vanderkooi
Jane M
JM
Hochstrasser
Robin M
RM
D016880:Anisotropy; D003198:Computer Simulation; D017666:Deuterium Oxide / Q000737:chemistry; D005990:Glycerol / Q000737:chemistry; D019791:Guanidine / Q000737:chemistry*; D008958:Models, Molecular; D017550:Spectroscopy, Fourier Transform Infrared; D014732:Vibration
D017666:Deuterium Oxide; D019791:Guanidine; D005990:Glycerol