ISOTOPIC SHIFT IN THE SPECTRUM OF CERIUM

Journal Article · Tue Jan 01 04:00:00 EST 1957 · Optika i Spektroskopiya

OSTI ID:4332624

Korostyleva, L A

The isotopic shifts between the components of isotopes Ce/sup 137/-Ce/ sup 138/-Ce/sup 140/ were determined. In addition am attempt was made to study in greater detail the isotopic shift of the spectrum of cerium between the components of the isotopes Cs/sup 140/-- Ce/sup 142/ and to determine from the isotopic shift the possible electron configurations of the levels taking part in energy transitions. The experimental set up was as follows: The source of light was an aluminum tube with a hollow cathode cooled by liquid air. A Fabry-Perrot interferometer served as the high resolution instrument amd was used in conjunction with a 3-prism Zeiss spectrograph (focal distance of the camera 84 cm). The coefficient of reflection of the silver coatings was about 90% in the region 4000 to 4500 A. The specimen was in the form of a cerium salt solution deposited on the hollow cathode and evaporated. The cerium spectrum was excited in a krypton atmosphere at a pressure of 1 mm Hg. The exposure was between 1.5 and 2 hours with a current of 100 ma. Kodak F-III films were used to photograph the spectra between 4000 amd 6500 A. Three specimens were used to obtain the isotopic shift: natural mixture of cerium isotopes, 50% mixture of isotopes of Ce/ sup 140/ and Ca/sup 142/, and an enriched cerium specimen consisting of 20.6% Ce/ sup 136/, 14.5% Ce/sup 138/, 61.8% Ce/sup 140/, and 3% Ce/sup 142/. The spectrograms were taken wth 20, 30, and 40 mm between the plates of the etalon. The isotopic shifi was measured between components of isotopes Ce/sup 140/ and Ce/ sup 142/ for 102 lines. All cerium lines have a negative shift. In four lines of enriched cerium the shift between the components of the isotopes Ce/sup 136/-- Ce/sup 138/- Ce/sup 140/ was determined by a graphical method and it was found that its magnitude is 0.26 of the shift between the components of the isotopes Ce/ sup 140/Ce/sup 142/. The results obtained are summarized. The experimental results established the existence of an anomaly in the isotopic shift in the spectrum of cerium between isotopes whose nuclei consist of 82 and 84 neutrons. It is concluded that in a transition from the isotope having 82 neutrons to the isotope having 84 neutrons, a completion of a shell occurs. The observed jump in the isotopic shift between the composition of the isotopes C/sup 140/-- Ce/sup 142/ appears to be a result of a sharp increase in the nuclear radius and a change in the charge distribution in the nucleus of the isotope with 84 neutrons. (TC0)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-12-011159
• OSTI ID: 4332624
• Journal Information: Optika i Spektroskopiya, Journal Name: Optika i Spektroskopiya Vol. Vol: 3
• Country of Publication: Country unknown/Code not available
• Language: Russian

Related Subjects

ATOMIC MODELS
CERIUM
CERIUM 136
CERIUM 137
CERIUM 138
CERIUM 140
CERIUM 142
ELECTRONS
ENERGY LEVELS
MEASURED VALUES
MIXING
NUCLEAR STRUCTURE
OPTICAL SYSTEMS
PHYSICS
RADIOISOTOPES
SALTS
SPECTRA
SPECTRAL SHIFT
SPECTROMETERS