The a7Cl(d, 3He)36S and 39K(d, 3He)3SAr reactions have been studied at a bombarding energy of 28.9 MeV. The results are compared with theoretical calculations for two or four holes in the sd-shell. The three-hole spectrum of 37C] is also briefly discussed. In the calculation for 3SAr, additional states of a two-particle four-hole nature are included. In 3SAr, the ground state and levels at 2.166 and 7.14 MeV are excited principally by l = 2 transfer, while transitions with appreciable l = 0 strength are observed to levels at 3. 935, 4.569, 5.158 and 5.563 MeV. This fragmentation is quite well reproduced by the inclusion of the 2p-4h states. In particular the level at 3,935 MeV is largely of this type, a conclusion supported by both the spectroscopic factors and ~ transition rates. The 36S ground state and levels at 6.511 and 7.12 MeV in 36S have angular distributions characteristic of l = 2. Three transitions with l = 0 strength are observed to levels at 3. 295, 4.523 and 4.577 MeV in this nucleus. An additional level was identified at 7.71 MeV but the/-transfer could not be determined. The data are only qualitatively reproduced by the four-hole calculation, which while useful in making probable jr assignments, suggests that core excitation is important here also.
This paper contains (1) the necessary mathematics for a precise interpretation of M~ssbauer data, and (2) a characterization of a spectrometer designed specifically to maximize the information available from these data. The innovative aspeizts of this spectrometer are that it provides a known absorber lineshape, that it is quantitative, and that it provides information on the vibrational states of the absorber via the second order Doppler shift vs temperature and the total absorption vs temperature. The spectrometer allows sample temperature and applied magnetic field to be varied in any combination of 2-350 K or 0-6 T, respectively. Simultaneous collection of four data streams allows an accurate representation of the transmission spectrum. Sophisticated computer treatment with extensive use of least squares fitting procedures and fast Fourier transform techniques provides the final output display of sample cross-section vs standardized source velocity. The crosssection display is shown to be independent of the thickness of samples with M6ssbauer eptical densities up to 3. In addition, we report the method and results of measurements which must precede the operation of the spectrometer: (1) the absorption coefficient of iron at 14 keV: (498___ 7)cm-1 , (2) the Debye temperature of our source (57Co in rhodium matrix): (361_+20) K, (3) the source lineshape: three Lorentzians with Heisenberg linewidth, a center line with twice the intensity of the symmetrically placed outer lines which are spaced 0.055 mm/s apart, (4) the MtSssbauer effect cross-section for 57Fe: (2.4_+ 0.2)× 10-18 cm 2 (5) the Debye temperature of iron (NBS /t 1541): (430_+ 30) K, and (6) the values for the Hamiltonian parameters of iron metal (NBS //1541) at 290, 101 and 4.2 K. The precision of the determined Hamiltonian parameters is defined in terms of a statistic with a weighted Z 2 distribution.
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