Experimental nuclear structure and decay data are evaluated for all the 17 known nuclides of mass 149 (Xe, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb). Detailed compiled and evaluated spectroscopic information is presented for each reaction and decay dataset, and recommended values are provided for level properties, α, β and γ radiations, and other spectroscopic parameters, based on an evaluation of all the available experimental data for A=149 isobaric nuclides. Although large amounts of nuclear spectroscopic data are available for nuclides of A=149, yet large gaps in knowledge exist, as described below. For the lowest atomic number nuclide ¹⁴⁹Xe, only the isotopic identification has been made, with no data for its ground-state half-life. For ¹⁴⁹Cs, ¹⁴⁹Tm and ¹⁴⁹Yb information is available for only the respective ground states. For ¹⁴⁹Ba, ¹⁴⁹La and ¹⁴⁹Er, limited data exist for excited states. Many of the decay schemes of radioactive nuclei of A=149 are considered as incomplete, either due to large energy differences between the highest observed excited states in daughter nuclides and the respective Q-values, or due to the lack of confirmed γ-ray data, as listed below: ¹⁴⁹Cs → ¹⁴⁹Ba, ¹⁴⁹Ba → ¹⁴⁹La, ¹⁴⁹La → ¹⁴⁹Ce, ¹⁴⁹Ce → ¹⁴⁹Pr, ¹⁴⁹Pr → ¹⁴⁹Nd, ¹⁴⁹Tb(4.17 min) → ¹⁴⁹Gd, ¹⁴⁹Ho(21.0 s and 56 s) → ¹⁴⁹Dy, ¹⁴⁹Er(4 s and 9.6 s) → ¹⁴⁹Ho, and ¹⁴⁹Tm → ¹⁴⁹Er. No data exist for the decay of ¹⁴⁹Yb to ¹⁴⁹Tm. Data for half-lives of the excited states in this mass chain are generally lacking as given below by the number of excited levels of known half-life / approximate number of known levels in a nuclide: 2/17 for ¹⁴⁹Ba, 0/18 for ¹⁴⁹La, 3/53 for ¹⁴⁹Ce, 3/44 for ¹⁴⁹Pr, 17/110 for ¹⁴⁹Nd, 9/90 for ¹⁴⁹Pm, 10/210 for ¹⁴⁹Sm, 2/125 for ¹⁴⁹Eu, 6/270 for ¹⁴⁹Gd, 5/200 for ¹⁴⁹Tb, 3/80 for ¹⁴⁹Dy, 3/90 for ¹⁴⁹Ho, and 3/14 for ¹⁴⁹Er. This work supersedes earlier evaluations of A=149 nuclides published by 2004Si16, 1994Si18, 1985Sz01 and 1976Ho17.

对质量为 149 的所有 17 种已知核素（Xe、Cs、Ba、La、Ce、Pr、Nd、Pm、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、是）。根据对 A=149 的所有可用实验数据的评估，为每个反应和衰变数据集提供了详细的编译和评估光谱信息，并为能级特性、α、β和γ辐射以及其他光谱参数提供了推荐值等压核素。尽管 A=149 的核素有大量的核光谱数据可用，但如下所述，知识上仍存在很大差距。对于原子序数最低的核素¹⁴⁹Xe，仅进行了同位素鉴定，没有关于其基态半衰期的数据。对于¹⁴⁹ Cs、¹⁴⁹ Tm 和¹⁴⁹ Yb，信息仅可用于各自的基态。对于¹⁴⁹ Ba、¹⁴⁹ La 和¹⁴⁹ Er，激发态的数据有限。A = 149 的放射性核的许多衰变方案被认为是不完整的，要么是由于子核素中观察到的最高激发态与各自的 Q 值之间存在很大的能量差异，要么是由于缺乏确认的γ射线数据, 如下所列：¹⁴⁹ Cs → ¹⁴⁹ Ba, ¹⁴⁹ Ba → ¹⁴⁹La, ¹⁴⁹ La → ¹⁴⁹ Ce, ¹⁴⁹ Ce → ¹⁴⁹ Pr, ¹⁴⁹ Pr → ¹⁴⁹ Nd, ¹⁴⁹ Tb(4.17 min) → ¹⁴⁹ Gd, ¹⁴⁹ Ho(21.0 s 和 56 s) → ¹⁴⁹ Dy, ¹⁴⁹ Er(4 s 和 9.6 s) → ¹⁴⁹ Ho，和¹⁴⁹ Tm → ¹⁴⁹ Er。没有关于¹⁴⁹ Yb衰变为¹⁴⁹ Tm 的数据。该质量链中激发态的半衰期数据通常缺乏，如下所示，由已知半衰期的激发能级数/核素中已知能级的近似数给出：^{149的 2/17}Ba, ¹⁴⁹ La 为0/18, ¹⁴⁹ Ce 为3/53, ¹⁴⁹ Pr 为3/44, ¹⁴⁹ Nd 为17/110, ¹⁴⁹ Pm 为9/90, ¹⁴⁹ Sm 为10/210, ¹⁴⁹ Eu为 2/125 , ¹⁴⁹ Gd 为 6/270, ¹⁴⁹ Tb 为 5/200, ¹⁴⁹ Dy 为3/80, ^{149 Ho 为 3/90, 149} Er为 3/14 。这项工作取代了 2004Si16、1994Si18、1985Sz01 和 1976Ho17 发表的 A=149 核素的早期评估。