A unique vibrational signature of rotated water monolayers on Pt(111): Predicted and observed

Six H-bonds in the periodic di-interstitial structure that accounts for scanning tunneling microscope images of root 37 and root 39 wetting layers on Pt(111) are some 0.2 angstrom shorter than H-bonds are in ice Ih. According to a broadly obeyed correlation, this density functional theory result implies a stringent test of the di-interstitial motif, namely the presence of an OH-stretch band red-shifted from that of ice Ih by more than 1000 cm(-1). Infrared absorption spectra satisfy the test, in showing a feature centered at about 1965 cm(-1), which grows in as deposited water orders. (C) 2011 American Institute of Physics. [doi:10.1063/1.3591966]