Nuclear Data Sheets for A = 172

The 1965 version of the Nuclear Data Sheets was revised according to experimental data received prior to May 1974, including approximately 120 papers. Data are presented for ten nuclei (Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, and Ir). Only alpha decay data are available for Os and Ir, only the half-life is known for Re, and no level scheme is known for Er. The Er(49.3 h) decay scheme is well established and provides the only data available on the Tm level scheme (16 levels, 9 J/sup π/ values, and 3 proposed rotational bands). The Tm(63.6 h), Lu(6.7 d), and /sup m/Yb(3.6 μs) decay schemes are compared, and suggested changes and discrepancies in the Yb level scheme are noted. These data as well as considerable reaction data and γ-multipolarity data establish the Yb level scheme, including 128 levels (45 J/sup π/ values) and 14 proposed rotational bands. Data on the Lu level scheme are available from Hf(1.87 y) decay and include 10 levels with J/sup π/ assignments. Two isomers (3.7 m and 440 μs) and their decays are also known for Lu. The Hf level scheme has been studied by Ta(36.8 m) decay and (xnγ) reactions and includes 34 levels (17 J/sup π/ values) with 3 proposed rotational bands. A preliminary decay scheme for W(6.7 m) suggests 4 levels and J/sup π/ assignments in Ta. (xnγ) reactions in W have established the ground-state band up to J/sup π/ = 14+. (U.S.)