Dear Psi4 developers and users,
I have done a B3LYP calculation first on a mixed basis set named LACVPs, with metal using LANL2DZ and other elements using 6-31G*. Then I would like to feed the converged wavefunction (npy file) of B3LYP/LACVPs for a calculation of a different basis set, say B3LYP/def2-SVP, to ensure the two calculations converge to the same electronic state. However, the new B3LYP/def2-SVP calculation is really hard to converge and finally converge to a completely different electronic state (B3LYP/def2-SVP has a <S^2> of 4.61 (absurdly high) and B3LYP/LACVPs has a <S^2> of 1.16, where the expected <S^2> =0.75). I also did another controlled experiment to narrow the range of this problem to the basis set projection with ECP, here specifically LANL2DZ. I define a new mix basis named DEFCVPs, with metal using LANL2DZ and other elements using def2-SVP. Then I repeat the procedure of feeding the npy file of B3LYP/LACVPs for a new calculation of B3LYP/DEFCVPs. This time the calculation proceeds well and converges to the same electronic state and has a <S^2> of 1.15). Any ideas about why this happens would be appreciated. Thank you!
PS: I have attached the two output files just in case anyone is interested to look at them.
Best,
Chenru
output-lacvps-def2svp.dat (25.2 KB) output-lacvps-defcvps.dat (21.2 KB)
