The crticial point properties characterize real space functions at a specific point, however the value outputted by basin analysis corresponds to the integral of a selected real space function over the whole basin, clearly their values must be very different. In other words, topology analysis focuses on revealing real space function values at some featured points, while basin analysis focuses on revealing total distribution amount of real space functions in certain local regions.There is no unique way of defining electron density of a bond. However, as the bond critical point is often regarded as the most representative point of a bond, you can study difference of electron density at BCP of a bond between different conformers to study how conformation change affects the electron density distribution on the corresponding bonding region.
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