The Chemical shift of deprotonated water dimer; path integral simulation

Shiga, Motoyuki   ; Suzuki, Kimichi*; Tachikawa, Masanori*

The 1H NMR chemical shift of deprotonated water dimer, HO, has been studied by ab initio path integral simulation. The simulation predicts that the isotropic shielding of hydrogen-bonded proton increases as a function of temperature. This change is about an order of magnitude larger than that of the non-hydrogen-bonded proton. It is concluded that this is caused by the significant difference in the quantum distribution of proton at high and low temperatures in the low barrier hydrogen bond.