ON ANOMALOUS CONVERSION COEFFICIENTS OF DIPOLE TRANSITIONS

Journal Article · Sat Mar 01 04:00:00 EST 1958 · Nuclear Phys.

DOI:https://doi.org/10.1016/0029-5582(58)90061-0· OSTI ID:4334416

Nilsson, S G; Rasmussen, J O

General aspects of the problem of anomalous nuclearstructure-dependent contributions to the internal-conversion proccss are considered in conjunction with highly retarded electric or magnetic dipole transitions. Formulas for an elememtary theory of anomalous internal eonversion for E1 tramsitions are given. Selection rules for the relevant nuclear m:itrix elements are given in the quantum numbers appropriate to spheroidally deformed nuclei (K, N, n /sub z/, LAMBDA , SIGMA ). Similar selection rules for M1 transitions are given on the basis of the anomalous operators previously derived by Church and Weneser. The experimemtal data on dipole conversion coefficients of retarded transitions for odd-mass spheroidal nuclei are surveyed. It is noted that where retardation is ascribable to K-forbiddeaness (up to retardation from the singleproton rate by a faetor of 10/sup 9/) no detectable anomalies are found, but where transitions are allowed by K-selection rules detectable conversion-coefficient anomalies may generally be found at retardations greater than 10/sup 5/ to 10/sup 6/ and are not found at lesser retardation. There are some exceptions to this general rule, though. From the present meager data the utility of selection rules in the asymptotic quantum numbers, N, n/sub z/, LAMBDA and SIGMA , for anomalousconversion matrix elements may be open to question, although their utility in qualitatively explaining retardation of the radiative transitions is very evident. The simple E1 theory is applied in an attempt to explain quantitatively the very anomalous 85-kev transition in Pa/sup 231/. Values of the two parameters in the simple theoretical expressions can be found to explain all three L- subshell conversion coefficients. The magnitude of one parameter, the nuclear matrix element , is consistent with estimates from the single-particle model. However, the magnitude required of the other parameter is such as to suggest that in the intranuclear process terms of higher order in the electromagnetic field thnn treated here may be of importance. (auth)

• Research Organization: Univ. of California, Berkeley
• NSA Number: NSA-12-006797
• OSTI ID: 4334416
• Journal Information: Nuclear Phys., Journal Name: Nuclear Phys. Vol. Vol: 5
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

BOUNDARY CONDITIONS
DEFORMATION
DIFFERENTIAL EQUATIONS
DIPOLES
DISTRIBUTION
ELECTRIC MOMENTS
ELECTROMAGNETIC FIELDS
FLUID FLOW
GASES
INTERNAL CONVERSION
MAGNETIC MOMENTS
MATHEMATICS
MATRICES
MECHANICS
MICROSCOPY
MOLECULES
NUCLEAR MODELS
NUCLEAR STRUCTURE
NUCLEAR THEORY
NUCLEI
PHYSICS
PROTACTINIUM 231
QUANTITATIVE ANALYSIS
QUANTUM MECHANICS
SELECTION RULES
SINGLE-PARTICLE MODEL
SPACE
TEMPERATURE
TRANSIENTS
VELOCITY