Application of the Correlation Consistent Composite Approach (ccCA) to Third-Row (Ga-Kr) Molecules

Area of Science:

• Computational chemistry
• Quantum chemistry
• Theoretical chemistry

Background:

• The G3/05 training set includes 51 energetic properties for atoms and molecules containing 4p elements (Ga-Kr).
• Accurate calculation of molecular energies is crucial for understanding chemical reactions and properties.

Purpose of the Study:

• To apply the correlation consistent composite approach (ccCA) to the G3/05 training set for 4p elements.
• To evaluate the accuracy of ccCA, especially with the inclusion of spin orbit coupling corrections.

Main Methods:

• The correlation consistent composite approach (ccCA) was employed.
• First-order and second-order spin orbit coupling corrections were incorporated into the calculations.
• Calculations were performed on atoms and molecules containing 4p elements (Ga-Kr).

Main Results:

• The ccCA method, with first-order spin orbit coupling corrections, achieved a mean absolute deviation (MAD) of 0.95 kcal mol(-1).
• This represents an improvement over existing G3 and G3X model chemistries.
• Including second-order spin orbit corrections further reduced the ccCA MAD to 0.88 kcal mol(-1).

Conclusions:

• The ccCA method demonstrates high accuracy for 4p elements, comparable to lighter main group elements.
• Spin orbit coupling corrections are essential for accurate calculations involving heavier elements like Ga-Kr.
• ccCA with spin orbit corrections offers a robust approach for theoretical chemistry studies of these elements.