Doublet structure of the negative-parity states in ${}^{195}\mathrm{Pt}$ supported by particle-rotor calculations

It is shown that particle-triaxial-rotor calculations with a Woods-Saxon potential for ${}^{195}\mathrm{Pt}$ reproduce the experimentally observed doublet structure of the excitation spectrum below 700 keV. The observed strong $B(E2)$ transition strengths are also well reproduced. The structure of every doublet is dominated by one out of two single-particle orbitals. The absolute values of the $E2$ transition probabilities obtained in the particle-rotor model are in overall agreement with the predictions made by assuming a U(6/12) supersymmetry. The ratios of $B(E2)$ values between the states of two doublets agree well with those obtained by assuming a pseudospin symmetry only. This supports the idea of a pseudospin nature of the doublet structure although no a priori assumptions are made concerning a pseudospin symmetry of the Hamiltonian.

Figure 1

(a), (c) Calculated and (b) experimental spectra of the excited states in ${}^{195}\mathrm{Pt}$ below 700 keV. The doublet levels are connected with a dotted line. The criterion for the assignment of doublets is discussed in the middle of Sec. 2. In the case of the PTRM spectrum, the number (31,32) of the quasineutron orbital dominating the wave function is also given in brackets.

Figure 2

Band structure assigned from strong $B(E2)$ transition strengths in $e^2{\mathrm{b}}^2$ between the doublet levels. Shown are the results of (a) the PTRM, (b) experiment, and (c) U(6/12). The energies (c) are taken from Ref. [4] and the $B(E2)$ values (c) are taken from Ref. [8].