Volume 125, Issue 24, 28 December 2006
Index of content:
125(2006); http://dx.doi.org/10.1063/1.2409924View Description Hide Description
Many schemes for calculating reaction rates and free energy barriers require an accurate reaction coordinate, but it is difficult to quantify reaction coordinate accuracy for complex processes like protein folding and nucleation. The histogram test, based on estimated committor probabilities, is often used as a qualitative indicator for good reaction coordinates. This paper derives the mean and variance of the intrinsic committor distribution in terms of the mean and variance of the histogram of committor estimates. These convenient formulas enable the first quantitative calculations of reaction coordinate error for complex systems. An example shows that the approximate transition state surface from Peters’ and Trout’s reaction coordinate for nucleation in the Ising model gives a mean committor probability of 0.495 and a standard deviation of 0.042.
Relativistic effective core potential calculations of Hg and eka-Hg (E112) interactions with gold: Spin-orbit density functional theory modeling of and systems125(2006); http://dx.doi.org/10.1063/1.2403850View Description Hide Description
Interactions of eka-Hg (E112) and Hg atoms with small gold clusters were studied in the frame of the relativistic effective core potential model using the density functional theory(DFT) approach incorporating spin-dependent (magnetic) interactions. The choice of the exchange-correlation functional was based on a comparison of the results of DFT and large-scale coupled cluster calculations for and at the scalar relativistic level. A close similarity between the and equilibrium structures was observed. The E112 binding energies on are typically smaller than those for Hg by ca. 25%–32% and the equilibrium separations are always slightly larger than their counterparts.