Pseudopotential-Based Correlation Consistent Composite Approach (rp-ccCA) for First- and Second-Row Transition Metal...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Thermochemistry

Background:

• Accurate calculation of enthalpies of formation (ΔHf) is crucial for predicting chemical reaction feasibility.
• Existing computational methods for transition metal compounds can be computationally expensive.

Purpose of the Study:

• To evaluate the accuracy and efficiency of the relativistic-pseudopotential correlation consistent composite approach (rp-ccCA) for calculating ΔHf.
• To develop a comprehensive dataset of ΔHf for second-row (4d) transition metal compounds.

Main Methods:

• The relativistic-pseudopotential correlation consistent composite approach (rp-ccCA) was employed.
• Calculated ΔHf values for 3d transition metal compounds were compared against experimental data and an all-electron composite method (ccCA-TM).
• A calibration set (4dHf-210) of 210 4d transition metal compounds was constructed using rp-ccCA.

Main Results:

• rp-ccCA demonstrated high accuracy for 3d transition metal compounds, within 3 kcal/mol of experimental data.
• The rp-ccCA method resulted in a 53% computational time saving compared to ccCA-TM.
• For the 4dHf-210 set, rp-ccCA showed a mean absolute deviation of 3.64 kcal/mol, comparable to experimental uncertainties.

Conclusions:

• rp-ccCA is a reliable and computationally efficient method for determining the enthalpy of formation for transition metal compounds.
• The 4dHf-210 dataset provides valuable energetics for computational and experimental chemists.
• This work aids in the development of new computational methodologies and reaction design.