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2nd analytical derivatives

The program aoforce computes force constants and IR and Raman Spectra on SCF and DFT level. Analytical second derivative calculations can directly be started from converged SCF or DFT calculations. Note, that the basis is restricted to $ d$-functions, and ROHF as well as broken occupation numbers are not allowed. For better efficiency, in case of larger systems, use the keyword $maxcor as described in Chapter 10 to reduce computational cost. RI will be used if the RI option for DFT has been specified.