Theoretical investigations of nuclear quantum effect on molecular magnetic properties based on multi-component density functional theory

We applied the multi-component density functional theory (MC_DFT) combined with the gauge – including atomic orbital (GIAO) and continuous set of gauge transformation (CSGT) techniques to some small molecules (H2, HD, H2O, CH4, etc.) for analyzing the nuclear quantum effect on molecular magnetic properties, such as nuclear magnetic shielding constant and molecular magnetic susceptibility. Our method clearly shows that the absolute isotropic magnetic shielding constant depends on the spatial distribution of quantum nuclei, that is, the deuteron-isotopomers have the weaker deshielding effect than the proton-isotopomers. We also found the magnetic isotope effect with respect to the molecular magnetic susceptibility, that is, the magnetic susceptibility of the deuteron-isotopomers is smaller than that of the proton-isotopomers.