Many thanks for your nice comments and clarifications.

Saeed

This difference (0.003) is completely negligible. Even the scale factors fitted by different researchers differ with each other much more than this magnitude. The negligible difference just demonstrated "Diffuse function do not affect scale factor".

Dear Tian,
Many thanks for your informative and valuable comment.
In the below data base:

Database of Frequency Scale Factors for Electronic Model Chemistries
S. Kanchanakungwankul, J. L. Bao, Date J. of Zheng, last −Version update: I. M. Alecu, July 5
22, B. 2021
J. Lynch, Y. Zhao, and D. G. Truhlar

The value of ZPVE-scale factor for M06-2X/6-31G(d,p) is found to be 0.965. On the other hand, this scale factor for the diffuse augmented variant M06-2X/6-31+G(d,p) is 0.968 which is slightly different from that of M06-2X/6-31G(d,p) indicating that diffuse functions somewhat affect the scale factor. This difference, while seems negligible, shows that your statement "Diffuse function do not affect scale factor" is not completely satisfied.

Please let me know if you have an evident reference for the statement "Diffuse function do not affect scale factor". Maybe, this would be questioned by referee why I have employed scale factor of M06-2X/6-31G(d,p) instead that for the practically employed level M06-2X/6-31++G(d,p) .

Sincerely yours,
Saeed

Use scale factor of M06-2X/6-31G(d,p) level, which should be able to be found. Diffuse function and dispersion correction do not affect scale factor.

Dear Tian,

Please, if possible, let me state that my current computations are performed at M06-2X-D3(0)/6-31++G(d,p) level. While I did search many data bases I have access them, I cannot find the ZPVE scale factor associated with this computational level. Please, send me this scale factor if you have corresponding value and, the related reference to be cited in the manuscript.

Sincerely yours,
Saeed