Argentina
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On the truncation of the number of excited states in density functional theory sum-over-states calculations of indirect spin spin coupling constants
Fecha
2015-12Registro en:
Zarycz, Maria Natalia Cristina; Provasi, Patricio Federico; Sauer, Stephan P. A.; On the truncation of the number of excited states in density functional theory sum-over-states calculations of indirect spin spin coupling constants; American Institute of Physics; Journal of Chemical Physics; 143; 24; 12-2015
0021-9606
1089-7690
CONICET Digital
CONICET
Autor
Zarycz, Maria Natalia Cristina
Provasi, Patricio Federico
Sauer, Stephan P. A.
Resumen
It is investigated, whether the number of excited (pseudo)states can be truncated in the sum-over-states expression for indirect spin-spin coupling constants (SSCCs), which is used in the Contributions from Localized Orbitals within the Polarization Propagator Approach and Inner Projections of the Polarization Propagator (IPPP-CLOPPA) approach to analyzing SSCCs in terms of localized orbitals. As a test set we have studied the nine simple compounds, CH4, NH3, H2O, SiH4, PH3, SH2, C2H2, C2H4, and C2H6. The excited (pseudo)states were obtained from time-dependent density functional theory (TD-DFT) calculations with the B3LYP exchange-correlation functional and the specialized core-property basis set, aug-cc-pVTZ-J. We investigated both how the calculated coupling constants depend on the number of (pseudo)states included in the summation and whether the summation can be truncated in a systematic way at a smaller number of states and extrapolated to the total number of (pseudo)states for the given one-electron basis set. We find that this is possible and that for some of the couplings it is sufficient to include only about 30% of the excited (pseudo)states.