A direct molecular orbital dynamics study on proton transfer in the diamond lattice

For the proton trapped in the C26H32 diamond cluster model, the effect of temperature on the trajectory activated by thermal energy has been simulated on the basis of newly developed direct molecular orbital dynamics calculations at the semi-empirical PM3 molecular orbital (MO) level. The static PM3-MO calculations showed that the proton is stabilized in the tetrahedral site of the cluster model. The simulation temperatures were chosen as 0, 100, 300 and 600 K. Up to 300 K, the amplitude of thermal vibration of the proton increases remarkably around the tetrahedral trapping site with increasing temperature. However, at 600 K it was found that the proton transfers to the next tetrahedral site through the hexagonal site at a time interval of 0.2 ps.