2,688 research outputs found
Scissors Modes:The first overtone
Scissors modes were predicted in the framework of the Two-Rotor Model. This
model has an intrinsic harmonic spectrum, so that the level above the Scissors
Mode, the first overtone, has excitation energy twice that of the Scissors
Mode. Since the latter is of the order of 3 MeV in the rare earth region, the
energy of the overtone is below threshold for nucleon emission, and its width
should remain small enough for the overtone to be observable. We find that
,
where is the zero-point oscillation amplitude, which in the rare
earth region is of order .Comment: 5 pages, Rapid Communication
Observation of Scissors Modes in solid state systems with a SQUID
The occurrence of scissors modes in crystals that have deformed ions in their
cells has been predicted some time ago. The theoretical value of their energy
is rather uncertain, however, ranging between 10 and a few tenths of eV, with
the corresponding widths of 10^-7, 10^-6 eV. Their observation by resonance
fluorescence experiments therefore requires a photon spectrometer covering a
wide energy range with a very high resolving power. We propose and discuss a
new experiment in which such difficulties are overcome by measuring with a
SQUID the variation of the magnetic field associated with the excitation of
scissors modes.Comment: 8 pages, 2 figure
A study of ground beetles (Carabidae, coleoptera) at adjacent woodland and grassland habitats in Durham, north-east England
Communities of Carabid beetles have been studied at adjacent woodland and grassland habitats in Durham, north-east England during the period 1988 May 12 to December 23.From a total of 25 Carabid species identified, the data obtained on a subset of some 17 species were sufficient to permit a discussion of the biological seasons of adult individuals. Many measurements have been taken of the frequency of capture, the distance of movement, the length of the mandible tip, the ratio of the length of the abdomen to that of the elytra, the numbers and volumes of eggs, and the maturity of the reproductive organs of both sexes. It is suggested that the results of the present work are compatible with those of previous studies of ground beetles at various habitats in north-west Europe, which have revealed a shift of the time of occurrence of the breeding and emergence seasons depending upon the harshness of the local environmental conditions. The composition of the communities of Carabid species at the Durham woodland and grassland sites has also been investigated. The dominant species in the two habitats were found to be Pterostichus madidus and Nebria brevicollis
- …