ADOPTED LEVELS for 179Tl

Author: Coral M. Baglin |  Citation: Nucl. Data Sheets 110, 265 (2009) |  Cutoff date: 15-Nov-2008 

 Full ENSDF file | Adopted Levels (PDF version) 


Q(β-)=-1.033×104 keV 9S(n)= 1.156×104 keV SYS(p)= -7.5×102 keV 5Q(α)= 6710 keV 5
Reference: 2012WA38

General Comments:

α decay from 179Tl:

α 6569 10 α from 179Tl(g.s.), and 7096 10 and 7213 10 α’s from a 0.0+x level are observed, and all are correlated with a 6435α from 175Au (1998To14). Thus, α’s from the 0.0+x level feed 175Au levels separated by 120 14 keV. Further, 1998To14 suggest that, unless the 6435α from 175Au is a doublet, the 6569α and 7213α feed either the same level in 175Au or levels connected by a prompt γ. However, from systematics, both 1/2+ and 11/2- isomeric states should exist in 175Au, and 2002Ro17 report both a 6438α and a 6412α from 175Au. Therefore, it seems probable that the 6435α of 1998To14 is indeed a doublet. Correlation data from 2002Ro17 imply that the stronger α from 179Tl(0+x) (i.e., the 7213α) feeds 175Au(11/2-) and the 6569α from 179Tl(g.s.) feeds 175Au(1/2+). If the 6569α is a g.s. to g.s. transition, then x |>659 keV for the 0.0+x level of 179Tl.

Q-value: Note: Current evaluation has used the following Q record

Q-value: Uncertainty is 200 keV and 120 keV in Q(β-) and S(n), respectively (2003Au03).





E(level)
(keV)
Jπ(level) T1/2(level)
  0.0 (1/2+) 0.23 s 4 
% α < 100
% ε = ?
% p = ?
  0.0+X (11/2-) 1.5 ms 3 
% α ≤ 100
% IT = ?
% ε = ?
% p = ?

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Additional Level Data and Comments:

E(level)Jπ(level)T1/2(level)Comments
  0.0+X(11/2-) 1.5 ms 3 
% α ≤ 100
% IT = ?
% ε = ?
% p = ?
Jπ(level): 187Tl, 185Tl, 183Tl have isomeric h9/2 states at 336, 454, 625, respectively, which deexcite via E3 transitions to a d3/2 level at E=250-300 keV. These energy systematics suggest that the corresponding states in 181Tl and 179Tl may occur near 850 and 1100 keV; from the E3 transition energy and T1/2 systematics, 1998To14 predict a T1/2 value for E3 deexcitation which is close to the level T1/2 observed for 181Tl but very much lower than T1/2=1.5 ms adopted for the 0.0+x level of 179Tl. 1998To14 suggest, therefore, that the h11/2 orbital may lie below the h9/2 orbital in 179Tl, allowing α decay to compete successfully with M4 γ deexcitation. Note that 177Tl has an isomeric (11/2-) level at E=807 18 (1999Po09).

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