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Proton spin-lattice relaxation times T1 were measured in mixtures of H2 with N2O as a function of density, composition, and temperature (200–400 K) in the region where [Formula: see text]. These data, along with the data obtained by Lalita and Bloom for H2–CO2, were interpreted, using Bloom–Oppenheim theory, to obtain the anisotropic intermoleeular potential parameters. Two models, (i) the Lennard–Jones (12–6) potential (LJP) and (ii) the modified Buckingham (exp-6) potential (MBP), were used to represent the isotropic part of the intermolecular potential. The relative anisotropy in the attractive r−6 term and the quadrupole moments of N2O and CO2 as obtained from MBP model are in better agreement with the values obtained from the polarizability data and the reported values, respectively, than those obtained from the LJP model.

Proton spin–lattice relaxation times have been measured in the gaseous mixtures CH4–N2 and CH4–CO2 as a function of density and composition in the temperature region 300–600 K. The values of T1/ρ extrapolated to 100% N2 and CO2 respectively were found to be proportional to T−n where n = 0.87 ± 0.14 for CH4–N2 and n = 0.91 ± 0.10 for CH4–CO2. It is not possible to fit these data using a hard sphere potential for the isotropic part. Using the Bloom–Oppenheim theory and assuming that the correlation time of the spin–rotation interaction can be approximated by the average lifetime of a molecule in the given J state, it is shown that the above temperature dependence can be fitted by a 12–6 Lennard–Jones potential combined with an appropriate anisotropic potential. We have obtained the strengths of the repulsive and attractive terms in the anisotropic potential by a least squares fit of the data. Using the known values of the quadrupole moments of N2 and CO2, the octopole moment of CH4 has been obtained.

Proton spin-lattice relaxation times, T1, have been measured in H2–Ar and H2–N2 gas mixtures as a function of density (10 1 data obtained by Foster and Rugheimer and by Williams in these mixtures below 300 K have been analysed using the Bloom–Oppenheim theory. Models for intermolecular potentials to explain the T1 data have been proposed. It is found that the relative anisotropy in the attractive part of the intermolecular potential which fits the T1 data best compares well with that evaluated using polarizability data.

In this paper quantitative determination of GIM in 30 apparently healthy subjects and 15 subjects with functional or organic alternations in the hypothalamic-hypophyseal axis is detailed. From the observations on the quantitati on of GIM in the varied clinical states the authors conclude that the hypothalamic region contributing GIM is different from that controlling the secretion and release of gonadotropins. This preliminary data also suggest that the quantitative determination of GIM may help to delineate hypogonadotropic hypogonadism due to pituitary disease from the hypothalamic etiology.