PNNL

Abstract

Six H-bonds in the periodic di-interstitial structure that accounts for STM images of "37"and "39" wetting layers on Pt(111) are some 0.2 Å shorter than H-bonds are in ice Ih. According to a broadly obeyed correlation, this Density Functional Theory (DFT) 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 showing a feature centered at about 1965 cm-1 satisfy the test. The DFT prediction is some 100 - 200 cm-1 higher, because it corresponds to a theoretical metal lattice expanded 1.0 linear percent relative to experiment.