Published by CSIRO PUBLISHING for CSIRO and the Australian Academy of Science
نویسنده
چکیده
A critical look is made of discrepancies and agreements between new and old measurements and theories for elastic and n = 2 excitation of atomic hydrogen by electron impact, mainly at 16 ·5, 54 and 100 eV. A discussion of earlier work indicates the contributions of Weigold and colleagues. The difficulties of observing and modelling small scattered fluxes at backward scattering angles and of making absolute cross section calibrations are noted. New measurements of elastic scattering at 16 ·5 eV confirm earlier measured angular distributions. An absolute calibration of the differential cross section at 16 ·5 eV gives agreement within one standard deviation with intermediate energy R-matrix and multi-pseudostate close coupling values. At 16 ·5 eV, measurements of the separate 2s and 2p differential cross sections and the lambda, R and I correlation parameters again support the values from those theories.
منابع مشابه
CSIRO PUBLISHING for CSIRO Australia and the Australian Academy of Science
A survey is given of experimental studies of electron attachment and recombination in dense molecular media, from which information on the effect of van der Waals potentials or on the existence of surrounding molecules on these processes is obtained.
متن کاملPublished by CSIRO PUBLISHING for CSIRO Australia and the Australian Academy of Science
Accurate low-energy electron scattering data are needed in many fields of physics. However, accurate experiments are difficult to design and to carry out. By 1967 low-energy electron–He cross sections had been measured by two different techniques, designed to provide accurate data. Unfortunately, the data differed by amounts well outside the estimated error bars. Despite the relative simplicity...
متن کاملHow energy and water availability constrain vegetation water-use along the North Australian Tropical Transect
Energy and water availability were identified as the first order controls of evapotranspiration(ET) in ecohyrodrology. With a ~1,000 km precipitation gradient and distinct wet-dry climate,the North Australian Tropical Transect (NATT) was well suited for evaluating how energy andwater availabilities constrain water use by vegetation, but has not been done yet. In this study,we addressed this que...
متن کاملCSIRO PUBLISHING for CSIRO Australia and the Australian Academy of Science
An optical study has been made of La0 ·7Ca0 ·3MnO3 and La0 ·8Li0 ·2MnO3 in the infrared spectral region (100 cm−1 to 4000 cm−1). The transmission of all samples is negligible. The photoconductive response is also unmeasurable. The data reported are therefore restricted to reflectivity measurements. At room temperature, both materials exhibit similar ‘bending’ and ‘stretching’ phonon modes, asso...
متن کاملA dataset for examining trends in publication of new Australian insects
Australian Faunal Directory data were used to create a new, publicly available dataset, nai50, which lists 18318 species and subspecies names for Australian insects described in the period 1961-2010, together with associated publishing data. The number of taxonomic publications introducing the new names varied little around a long-term average of 70 per year, with ca 420 new names published per...
متن کامل