INVESTIGADORES
MALDONADO alejandro Fabian
artículos
Título:
Nuclear charge-distribution effects on the NMR spectroscopy parameters
Autor/es:
ALEJANDRO F. MALDONADO; CARLOS A. GIMENEZ; GUSTAVO A. AUCAR
Revista:
JOURNAL OF CHEMICAL PHYSICS
Editorial:
AMER INST PHYSICS
Referencias:
Lugar: Chicago; Año: 2012 vol. 136 p. 224110 - 224118
ISSN:
0021-9606
Resumen:
We present here a first systematic study about the influence of the size and type of nuclear models (Gaussian and point-like) onthe NMR spectroscopic parameters, the nuclear magnetic shielding σ and the indirect nuclear spin J-coupling. We found thatrelativistic effects largely enhance the nuclear size, NSE effects on that parameters being them quite sensitive to the nuclear sizeadopted for calculations.Results for two rare-gas atoms (Kr, Rn) and few molecular systems like HX, (X = Br, I, At), CH4 , SnH4 , SnIH3 , SnI2 H2 andPbIH3 are presented. J-couplings are more sensitive than shieldings in both, relativistic and NR regimes. The highest effect(close to ∼ 11% of variation in relativistic calculations with that two different nuclear models) is observed for J(Pb-I) in PbIH3 .A similar effect is found for J(Pb-H) in the same molecule, of 9%.The NSE effect is lightly dependent on vicinal atoms. For σ(Sn) in SnI4−n Hn with n = 1, 2 it is as large as of few ppm (between3 to 8.56 ppm). For J(Sn-H) in this set of molecules it goes from 37 Hz for SnH4 to 54 Hz for SnI2 H2 .We also studied the NSE effects on the atomic and molecular ground-state electronic energies. We found that these effects areonly important within the relativistic regime but not within the non relativistic (NR) one. They are in good agreement withprevious works.