The single donator-single acceptor hydrogen bonding structure in water probed by Raman spectroscopy

In this work, the Raman spectra of aqueous C(12)E(5) solutions are recorded and utilized to demonstrate the existence of single donator-single acceptor (DA) hydrogen bonding in water. From Raman OH stretching bands of aqueous C(12)E(5) solutions, the relative intensity of 3430 cm(-1) subband increases with C(12)E(5) concentrations. For confined water, the DA hydrogen bonding can be expected to be the important hydrogen bonding species. Therefore, the 3430 cm(-1) component can be ascribed to OH vibration engaged in DA hydrogen bonding. This is in agreement with our recent explanation on Raman OH stretching band of water. For water at ambient conditions, the double donor-double acceptor (DDAA) and DA should be the dominant hydrogen bonding species, the ratio of DDAA to DA can be approximately to be 0.75:1, and the mean hydrogen bonding can be determined to be 2.75.