Thank you for your offer to help!
I think I will first try to use the approximation you recommend and compare the results to QM computations to verify it is a good enough approximation.
If I understand the Glycam06 paper correctly, I will need to generate a rotational energy curve for the rotation about the Cg-Os bond for my molecule at the B3LYP/6-31++G(2d,2p)//HF/6-31G* level of theory and then to compare this curve to the GLYCAM06 result.
--Can you explain how I generate the rotational energy curve from the GLYCAM06 parameters?
If I were to have to develop my own parameters, would it be correct to use two simple compounds (methyl methoxyacetate and tetrahydro-2H-pyran-2-yl acetate) as a training set to generate the parameters?
Here, I am not completely clear on how the fitting of the parameter terms was performed (in terms of the math involved) and how the rotational energy curve was divided into the respective atomic sequences (as opposed to using just a single atomic sequence in GLYCAM93).
Thank you again!