I am referring Article Theoretical studies on electrochemistry of p-aminophenol
paper for calculating the theoretical redox potential using the described in this paper. I reproduce the DFT calculations using B3LYP/6-31G(d,p) level of theory and the Excel file containing the free energy calculations are attached.The following values are reported in the paper
DGº 1 (kJ/mol) = -115.596
DGº 2 (kJ/mol) = -44.433
DGº 3 (kJ/mol) = -28.424
as per Born-Haber cycle:
DGº (kJ/mol) = DGº 1 - DGº 2 + DGº 3 =-131.605
DGº 2 and DGº 3 are solvation-free energies for oxidized and reduced forms.
Eº=DGº/(n*F) = -131.605/(-2*96.485)=0.682 V
In my calculation following values were obtained:
DGº 1 (kJ/mol) = -115.559
DGº 2 (kJ/mol) = -26.587
DGº 3 (kJ/mol) = -23.635
DGº (kJ/mol) = DGº 1 - DGº 2 + DGº 3 =-112.607
Eº=DGº/(n*F) = -112.607/(-2*96.485)=0.584 V
I calculated
DGº 2 = Gº(p_PA)(sol)- Gº(p_PA)(gas)
similarly
DGº 3 =Gº(p_Q)(sol)- Gº(p_Q)(gas)
I used PCM model for solvation with water as a solvent, as mentioned in the paper, using scrf=(pcm,solvent=water) keywords in the input file.
I cannot understand why DGº 2 and DGº 3 differ from the calculations in the paper.
Any help is highly appreciated.
Thanks
Please see this file instead of the file attached with the question to check the calculations I did to get DGº2 and DGº3 .
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