Premium
Nuclear spin relaxation of oxygen‐17, silicon‐29 and carbon‐13 in octamethylcyclotetrasiloxane
Author(s) -
Kowalewski Jozef,
Berggren Elisabet
Publication year - 1989
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260270416
Subject(s) - octamethylcyclotetrasiloxane , chemistry , relaxation (psychology) , dipole , spin–lattice relaxation , oxygen 17 , isotropy , condensed matter physics , electric field gradient , ab initio quantum chemistry methods , ab initio , nuclear magnetic resonance , molecular physics , atomic physics , quadrupole , physics , paramagnetism , organic chemistry , psychology , social psychology , quantum mechanics , molecule , polymer chemistry
17 O, 13 C and 29 Si nuclear magnetic relaxation data are reported for neat liquid octamethylcyclotetrasiloxane in the temperature range 298–373 K. The electric field gradient at the site of the oxygen nucleus is estimated by ab initio calculations and the 17 O relaxation data are interpreted in terms of isotropic rotational diffusion. The 13 C dipole‐dipole relaxation rates are interpreted in terms of the Woessner model for internal methyl rotation superimposed on the isotropic overall tumbling. The 29 Si spin‐lattice relaxation is composed of dipole‐dipole and spin‐rotation contributions, which are interpreted in a semi‐quantitative fashion.