A catalyst don’t appear in the overall stoichiometry of the reaction it catalyzes, COA of Formula: C14H32N4, but it must appear in at least one of the elementary reactions in the mechanism for the catalyzed reaction. 41203-22-9, Name is 1,4,8,11-Tetramethyl-1,4,8,11-tetraazacyclotetradecane, molecular formula is C14H32N4. In a Article, authors is Proppe, Jonny£¬once mentioned of 41203-22-9
Reliable Estimation of Prediction Uncertainty for Physicochemical Property Models
One of the major challenges in computational science is to determine the uncertainty of a virtual measurement, that is the prediction of an observable based on calculations. As highly accurate first-principles calculations are in general unfeasible for most physical systems, one usually resorts to parameteric property models of observables, which require calibration by incorporating reference data. The resulting predictions and their uncertainties are sensitive to systematic errors such as inconsistent reference data, parametric model assumptions, or inadequate computational methods. Here, we discuss the calibration of property models in the light of bootstrapping, a sampling method that can be employed for identifying systematic errors and for reliable estimation of the prediction uncertainty. We apply bootstrapping to assess a linear property model linking the 57Fe Moessbauer isomer shift to the contact electron density at the iron nucleus for a diverse set of 44 molecular iron compounds. The contact electron density is calculated with 12 density functionals across Jacob’s ladder (PWLDA, BP86, BLYP, PW91, PBE, M06-L, TPSS, B3LYP, B3PW91, PBE0, M06, TPSSh). We provide systematic-error diagnostics and reliable, locally resolved uncertainties for isomer-shift predictions. Pure and hybrid density functionals yield average prediction uncertainties of 0.06-0.08 mm s-1 and 0.04-0.05 mm s-1, respectively, the latter being close to the average experimental uncertainty of 0.02 mm s-1. Furthermore, we show that both model parameters and prediction uncertainty depend significantly on the composition and number of reference data points. Accordingly, we suggest that rankings of density functionals based on performance measures (e.g., the squared coefficient of correlation, r2, or the root-mean-square error, RMSE) should not be inferred from a single data set. This study presents the first statistically rigorous calibration analysis for theoretical Moessbauer spectroscopy, which is of general applicability for physicochemical property models and not restricted to isomer-shift predictions. We provide the statistically meaningful reference data set MIS39 and a new calibration of the isomer shift based on the PBE0 functional.
I hope this article can help some friends in scientific research. I am very proud of our efforts over the past few months and hope to 41203-22-9, help many people in the next few years.COA of Formula: C14H32N4
Reference£º
Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI