TY - JOUR
T1 - Effect of hydrogen-bond on ultrafast spectral diffusion dynamics of water at charged monolayer interfaces
AU - Inoue, Ken ichi
AU - Ahmed, Mohammed
AU - Nihonyanagi, Satoshi
AU - Tahara, Tahei
N1 - Funding Information:
We thank Professor Tatsuya Ishiyama and Professor Aki-hiro Morita for giving unpublished information about the sign of hyperpolarizability of symmetric N–H stretch vibration. This work was partly supported by JSPS KAKENHI Grant Nos. JP25104005, 18H03905, and 18H05265. K.I. acknowledges the Special Postdoctoral Researchers (SPDR) program of RIKEN.
Publisher Copyright:
© 2019 Author(s).
PY - 2019/2/7
Y1 - 2019/2/7
N2 - Ultrafast hydrogen-bond fluctuation dynamics of water at charged monolayer interfaces were studied by the use of steady-state and 2D heterodyne-detected vibrational sum frequency generation (HD-VSFG) spectroscopy. Specifically, the effect of hydrogen-bond ability of the interface on the dynamics was investigated by comparing two monolayer interfaces that provide different hydrogen bond abilities: hydrogen bonding octadecylammonium (ODA) monolayer (pH = 2) and non-hydrogen bonding 1,2-dipalmitoyl-3-trimethyl-ammonium propane (DPTAP) monolayer. The steady-state HD-VSFG spectra and their ionic strength dependence revealed that water molecules at both of ODA and DPTAP interfaces are H-down oriented, pointing their H away from the interface, and that the contributions of the electrical double layer in the interfacial spectra of these interfaces are comparable to each other. However, 2D HD-VSFG data clearly indicated that the ultrafast hydrogen-bond fluctuation of water at the ODA interface is significantly suppressed, compared to that at the DPTAP interfaces. The obtained results suggest that the hydrogen-bond fluctuation of the topmost interfacial water at a positively charged interface is significantly affected by the hydrogen-bonding ability of the interface even in the case that the interfacial water molecules act as a hydrogen-bond acceptor to the head group of the monolayer.
AB - Ultrafast hydrogen-bond fluctuation dynamics of water at charged monolayer interfaces were studied by the use of steady-state and 2D heterodyne-detected vibrational sum frequency generation (HD-VSFG) spectroscopy. Specifically, the effect of hydrogen-bond ability of the interface on the dynamics was investigated by comparing two monolayer interfaces that provide different hydrogen bond abilities: hydrogen bonding octadecylammonium (ODA) monolayer (pH = 2) and non-hydrogen bonding 1,2-dipalmitoyl-3-trimethyl-ammonium propane (DPTAP) monolayer. The steady-state HD-VSFG spectra and their ionic strength dependence revealed that water molecules at both of ODA and DPTAP interfaces are H-down oriented, pointing their H away from the interface, and that the contributions of the electrical double layer in the interfacial spectra of these interfaces are comparable to each other. However, 2D HD-VSFG data clearly indicated that the ultrafast hydrogen-bond fluctuation of water at the ODA interface is significantly suppressed, compared to that at the DPTAP interfaces. The obtained results suggest that the hydrogen-bond fluctuation of the topmost interfacial water at a positively charged interface is significantly affected by the hydrogen-bonding ability of the interface even in the case that the interfacial water molecules act as a hydrogen-bond acceptor to the head group of the monolayer.
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U2 - 10.1063/1.5081077
DO - 10.1063/1.5081077
M3 - Article
C2 - 30736682
AN - SCOPUS:85061287505
VL - 150
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 5
M1 - 054705
ER -