Far Infrared Properties of Lattice Resonant Modes. I. Isotope Shifts

The frequency shift of a lattice resonant mode associated with the isotopic substitution of an impurity ion has been measured for NaCl: Cu+, KI: Ag+, and KBr: Li+. For all three systems, the experimental frequency shifts can be described satisfactorily by an Einstein oscillator representation for the resonant mode with the oscillator mass set equal to the impurity-ion mass. The model of Benedek and Nardelli and also Klein does not account for the experimental results of NaCl: Cu+ or KBr: Li+. The inclusion of anharmonic forces does improve the agreement between theory and experiment, but a large discrepancy still exists for KBr: Li+

The submillimeter spectra of the planets: Narrow-band photometry

Multicolor submillimeter observations of Jupiter, Saturn, Mars, and Uranus are reported. Narrow-band filters are used to define three passbands between 300 and 1600 μm to give accurate spectrophotometric data. A method for determining the atmospheric opacity from a single set of multicolor observations of a known source is shown to be consistent with secant plot data taken during very stable observing conditions. Such extinction data show that in the submillimeter region significant fluctuations in opacity occur over periods as short as 1 hr. At the time of observation the rings of Saturn were nearly edge-on and thus the disc brightness is determined without contribution from the ring emission. Comparisons with data obtained at earlier epochs give an estimate of the ring brightness as a function of wavelength. The disc emission spectra for Saturn, Jupiter, and Uranus are compared with various atmospheric models and other observations

Bolometric detectors as ion energy spectrometers

The response of a composite infrared bolometer to 5.4 MeV α particles from a 241Am source is examined. The bolometer consists of a 1 mm × 3 mm × 0.3 mm thick germanium thermometric element bonded to a sapphire substrate 50 μm thick and 6 mm in diameter. It operates at a temperature near 0.35 K. Slow voltage signals from the bolometer were converted to pulses and pulse height spectra were recorded. Energy resolutions of 60 keV (fwhm) were observed for particles interacting with the sapphire absorber. Other structure arising from interactions with other bolometer components was also observed. A 100-fold improvement in resolution is theoretically possible with bolometers of this type

Submillimeter observations of the asteroid 10 hygiea

We report the first successful ground-based observations of any asteroid at submillimeter wave-lengths. Observations of the asteroid 10 Hygiea at 370 and 770 μm are combined with observations in the near and thermal infrared (2.2, 10.6, and 21 μm) to study the thermal properties of Hygiea's regolith. The “standard” (nonrotating) thermal model is consistent with the entire data set, although a rotating thermophysical model with a “lunarlike” thermal inertia cannot be ruled out