We need to know how sensitive ZPE and vibrational properties are to choices of adjustable parameters in finite displacement methods. For example,
How much does the ZPE change as we adjust the displacement step size?
How much do the vibrational frequencies change if we rotate the molecule?
The answers are "not at all" in theory, but they will be nonzero in practice. Knowing the size of this limit tells us how close are approximate Hessians are to "exact."
WardLT
commented
10 months ago
We need to know how sensitive ZPE and vibrational properties are to choices of adjustable parameters in finite displacement methods. For example,
The answers are "not at all" in theory, but they will be nonzero in practice. Knowing the size of this limit tells us how close are approximate Hessians are to "exact."