鉕嘅同位素
鉕係唯一嘅鑭系元素同僅有嘅兩個元素喺頭82之間,而冇穩定(或甚至長壽命)嘅同位素之一。呢個係液滴模型一個好少發生嘅影響同相鄰元素嘅同位素嘅穩定性產生嘅結果,亦係頭84個之中最唔穩定嘅。衰變產物主要係釹同釤同位素(鉕-146衰變兩種,輕啲嘅同位素通常通過正電子衰變同電子捕獲產生釹,重啲嘅同位素通過β衰變產生釤)。鉕核異構體可能衰減到其他嘅鉕同位素同,一種同位素(鉕-145)有非常罕見鐠嘅α衰變模式。
最穩定嘅同位素係鉕-145,特定活性係940次(35太貝可)/ g,半衰期係17.7年。因為佢有84粒中子(比82多出2,呢個係一個對應喺一個穩定中子嘅組態),佢可以發射α粒子(其中有兩個中子),以形成鐠-141同82個中子。因此,佢係唯一嘅鉕從實驗觀察到α衰變嘅同位素,佢部分嘅α衰變嘅半衰期大概係6.3×109年,鉕-145細胞核以呢種方式衰減嘅相對概率係2.8×10-7%。其他幾個Pm同位素(鉕-144、鉕-146、鉕-147等)亦有正面α衰變嘅能量釋放,預測佢哋嘅α衰變會發生嘅,但都冇被觀察到。
呢個元素亦有18個核嘅異構體,質量數係133〜142、144、148、149、152同154(一啲質量數有一個以上嘅異構體)。最穩定嘅係鉕-148m,有43.1日嘅半衰期;呢個係比所有鉕同位素嘅基態嘅半衰期長,除咗鉕-143~147(鉕-148m有一個較比鉕-148基態長嘅半衰期)。
圖表
編輯符號 | Z(p) | N(n) | 質量(u) | 半衰期 | 原子核自旋 | 相對豐度 | 相對豐度嘅變化率 |
---|---|---|---|---|---|---|---|
激發能量 | |||||||
126Pm | 61 | 65 | 125.95752(54)# | 0.5# s | |||
127Pm | 61 | 66 | 126.95163(64)# | 1# s | 5/2+# | ||
128Pm | 61 | 67 | 127.94842(43)# | 1.0(3) s | 6+# | ||
129Pm | 61 | 68 | 128.94316(43)# | 3# s [>200 ns] | 5/2+# | ||
130Pm | 61 | 69 | 129.94045(32)# | 2.6(2) s | (5+,6+,4+) | ||
131Pm | 61 | 70 | 130.93587(21)# | 6.3(8) s | 5/2+# | ||
132Pm | 61 | 71 | 131.93375(21)# | 6.2(6) s | (3+) | ||
133Pm | 61 | 72 | 132.92978(5) | 15(3) s | (3/2+) | ||
133mPm | 130.4(10) keV | 10# s | (11/2-) | ||||
134Pm | 61 | 73 | 133.92835(6) | 22(1) s | (5+) | ||
134mPm | 0(100)# keV | ~5 s | (2+) | ||||
135Pm | 61 | 74 | 134.92488(6) | 49(3) s | (5/2+,3/2+) | ||
135mPm | 50(100)# keV | 40(3) s | (11/2-) | ||||
136Pm | 61 | 75 | 135.92357(8) | 107(6) s | (5-) | ||
136mPm | 130(120) keV | 47(2) s | (2+) | ||||
137Pm | 61 | 76 | 136.920479(14) | 2# min | 5/2+# | ||
137mPm | 150(50) keV | 2.4(1) min | 11/2- | ||||
138Pm | 61 | 77 | 137.919548(30) | 10(2) s | 1+# | ||
138mPm | 30(30) keV | 3.24(5) min | 5-# | ||||
139Pm | 61 | 78 | 138.916804(14) | 4.15(5) min | (5/2)+ | ||
139mPm | 188.7(3) keV | 180(20) ms | (11/2)- | ||||
140Pm | 61 | 79 | 139.91604(4) | 9.2(2) s | 1+ | ||
140mPm | 420(40) keV | 5.95(5) min | 8- | ||||
141Pm | 61 | 80 | 140.913555(15) | 20.90(5) min | 5/2+ | ||
141m1Pm | 628.40(10) keV | 630(20) ns | 11/2- | ||||
141m2Pm | 2530.9(5) keV | >2 µs | |||||
142Pm | 61 | 81 | 141.912874(27) | 40.5(5) s | 1+ | ||
142mPm | 883.17(16) keV | 2.0(2) ms | (8)- | ||||
143Pm | 61 | 82 | 142.910933(4) | 265(7) d | 5/2+ | ||
144Pm | 61 | 83 | 143.912591(3) | 363(14) d | 5- | ||
144m1Pm | 840.90(5) keV | 780(200) ns | (9)+ | ||||
144m2Pm | 8595.8(22) keV | ~2.7 µs | (27+) | ||||
145Pm | 61 | 84 | 144.912749(3) | 17.7(4) a | 5/2+ | ||
146Pm | 61 | 85 | 145.914696(5) | 5.53(5) a | 3- | ||
147Pm | 61 | 86 | 146.9151385(26) | 2.6234(2) a | 7/2+ | ||
148Pm | 61 | 87 | 147.917475(7) | 5.368(2) d | 1- | ||
148mPm | 137.9(3) keV | 41.29(11) d | 5-,6- | ||||
149Pm | 61 | 88 | 148.918334(4) | 53.08(5) h | 7/2+ | ||
149mPm | 240.214(7) keV | 35(3) µs | 11/2- | ||||
150Pm | 61 | 89 | 149.920984(22) | 2.68(2) h | (1-) | ||
151Pm | 61 | 90 | 150.921207(6) | 28.40(4) h | 5/2+ | ||
152Pm | 61 | 91 | 151.923497(28) | 4.12(8) min | 1+ | ||
152m1Pm | 140(90) keV | 7.52(8) min | 4- | ||||
152m2Pm | 250(150)# keV | 13.8(2) min | (8) | ||||
153Pm | 61 | 92 | 152.924117(12) | 5.25(2) min | 5/2- | ||
154Pm | 61 | 93 | 153.92646(5) | 1.73(10) min | (0,1) | ||
154mPm | 120(120) keV | 2.68(7) min | (3,4) | ||||
155Pm | 61 | 94 | 154.92810(3) | 41.5(2) s | (5/2-) | ||
156Pm | 61 | 95 | 155.93106(4) | 26.70(10) s | 4- | ||
157Pm | 61 | 96 | 156.93304(12) | 10.56(10) s | (5/2-) | ||
158Pm | 61 | 97 | 157.93656(14) | 4.8(5) s | |||
159Pm | 61 | 98 | 158.93897(21)# | 1.47(15) s | 5/2-# | ||
160Pm | 61 | 99 | 159.94299(32)# | 2# s | |||
161Pm | 61 | 100 | 160.94586(54)# | 700# ms | 5/2-# | ||
162Pm | 61 | 101 | 161.95029(75)# | 500# ms | |||
163Pm | 61 | 102 | 162.95368(86)# | 200# ms | 5/2-# |
備註:有#嘅數據代表冇經過實驗嘅證明,只係理論推測,而用咗括號括係代表數據唔確定。
參攷
編輯- Isotope masses from Ame2003 Atomic Mass Evaluation by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in Nuclear Physics A729 (2003).
- Isotopic compositions and standard atomic masses from Atomic weights of the elements. Review 2000 (IUPAC Technical Report). Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and Atomic Weights Revised (2005).
- Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
- Audi, Bersillon, Blachot, Wapstra. The Nubase2003 evaluation of nuclear and decay properties, Nuc. Phys. A 729, pp. 3-128 (2003).
- National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the NuDat 2.1 database (retrieved Sept. 2005).
- David R. Lide (ed.), Norman E. Holden in CRC Handbook of Chemistry and Physics, 85th Edition, online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.
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