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The 91.5 cm telescope of NASA's Kuiper Airborne Observatory has been used, in conjunction with an InSb heterodyne receiver, to detect the J = 4-3 submillimeter transition of CO (461 GHz) and the 414−321 transition of H2O (380 GHz). The water emission was detected from the Orion “plateau” region.

Liquid helium cooled InSb hot electron bolometers are used in a balanced mixer configuration as detectors for an imageless microwave receiver. The system is designed for mounting at the prime focus of the National Radio Astronomy Observatory (NRAO) 11 m antenna at Kitt Peak, Arizona, and is suitable for the study of rotational line spectra of interstellar gas molecules. Currently the operating frequency is in the 90–140 GHz band where the double sideband system noise temperature is 250 K.

The EPR spectra of Gd3+, Yb3+, and Er3+ in diamagnetic garnet hosts have been measured as uniaxial pressures were applied to the crystal, and the parameters ∂gkl/∂eij and ∂Dkl/∂eij evaluated. A theory connecting these parameters with the magnetoelastic energy of the rare‐earth iron garnets has been developed, and the single‐ion contribution to the magnetostriction constants λ100 and λ111 of GdIG, YbIG, and ErIG calculated. In most cases the predicted single‐ion magnetostriction constants are of the same sign and within a factor of 2 of the observed magnetostriction constants at low temperatures. We conclude that single‐ion effects play a dominant role in the magnetoelastic behavior of the rare‐earth iron garnets.