请输入您要查询的百科知识：

　

词条 Isotopes of roentgenium
释义

  1. List of isotopes

      Notes  

  2. Isotopes and nuclear properties

     Nucleosynthesis  Cold fusion  As decay product  Nuclear isomerism  Chemical yields of isotopes  Cold fusion  Theoretical calculations  Evaporation residue cross sections 

  3. References

{{infobox roentgenium isotopes}}

Roentgenium (111Rg) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was 272Rg in 1994, which is also the only directly synthesized isotope; all others are decay products of nihonium, moscovium, and tennessine, and possibly copernicium, flerovium, and livermorium. There are 7 known radioisotopes from 272Rg to 282Rg. The longest-lived isotope is 282Rg with a half-life of 2.1 minutes, although the unconfirmed 283Rg and 286Rg may have a longer half-life of about 5.1 minutes and 10.7 minutes respectively.

List of isotopes

nuclide
symbol		 Z(p) N(n)  
isotopic mass (u)
 		 half-life decay
mode(s)[1]		 daughter
isotope(s)		 nuclear
spin and
parity
272Rg 111 161 272.15327(25)# 2.0(8) ms
[3.8(+14−8) ms]		 α 268Mt 5+#,6+#

274Rg[2] 111 163 274.15525(19)# 6.4(+307−29) ms α 270Mt

278Rg[3] 111 167 278.16149(38)# 4.2(+75−17) ms α 274Mt
279Rg[4] 111 168 279.16272(51)# 0.17(+81−8) s α 275Mt
280Rg[5]111169280.16514(61)#3.6(+43−13) s α (87%) 276Mt
EC (13%)[6] 280Ds
281Rg[7]111170281.16636(89)#17 (+6−3) s SF (90%) (various)
α (10%) 277Mt
282Rg[8] 111 171 282.16912(72)# 2.1 (+1.4-0.6) min[9] α 278Mt
283Rg[10] 111 172 283.17054(79)# 5.1 min? SF (various)
286Rg[11] 111 175 10.7 min? α 282Mt
1. ^Abbreviations:
SF: Spontaneous fission
2. ^Not directly synthesized, occurs as a decay product of 278Nh
3. ^Not directly synthesized, occurs as a decay product of 282Nh
4. ^Not directly synthesized, occurs in decay chain of 287Mc
5. ^Not directly synthesized, occurs in decay chain of 288Mc
6. ^http://xxx.lanl.gov/pdf/1502.03030.pdf
7. ^Not directly synthesized, occurs in decay chain of 293Ts
8. ^Not directly synthesized, occurs in decay chain of 294Ts
9. ^{{cite journal |last1=Khuyagbaatar |first1=J. |last2=Yakushev |first2=A. |last3=Düllmann |first3=Ch. E. |title=48Ca+249Bk Fusion Reaction Leading to Element Z=117: Long-Lived α-Decaying 270Db and Discovery of 266Lr |journal=Physical Review Letters |volume=112 |issue=17 |pages=172501 |year=2014 |doi=10.1103/PhysRevLett.112.172501 |display-authors=etal |bibcode=2014PhRvL.112q2501K |pmid=24836239}}
10. ^Not directly synthesized, occurs in decay chain of 287Fl and possibly 299Ubn; unconfirmed
11. ^Not directly synthesised, occurs in decay chain of 290Fl and 294Lv; unconfirmed
12. ^1 {{Cite journal |first=Peter |last=Armbruster |lastauthoramp=yes |first2=Gottfried |last2=Munzenberg |title=Creating superheavy elements |journal=Scientific American |volume=34 |pages=36–42 |year=1989}}
13. ^{{cite journal |last1=Barber |first1=Robert C. |last2=Gäggeler |first2=Heinz W. |last3=Karol |first3=Paul J. |last4=Nakahara |first4=Hiromichi |last5=Vardaci |first5=Emanuele |last6=Vogt |first6=Erich |title=Discovery of the element with atomic number 112 (IUPAC Technical Report) |journal=Pure and Applied Chemistry |volume=81 |issue=7 |page=1331 |year=2009 |doi=10.1351/PAC-REP-08-03-05}}
14. ^{{cite journal |last1=Fleischmann |first1=Martin |last2=Pons |first2=Stanley |year=1989 |title=Electrochemically induced nuclear fusion of deuterium |journal=Journal of Electroanalytical Chemistry and Interfacial Electrochemistry |volume=261 |issue=2 |pages=301–308 |doi=10.1016/0022-0728(89)80006-3 |url=http://www.sciencedirect.com/science/article/pii/0022072889800063 |accessdate=15 October 2012}}
15. ^1 {{Cite journal |doi=10.1007/BF01291182 |title=The new element 111 |year=1995 |last=Hofmann |first=S. |journal=Zeitschrift für Physik A |volume=350 |pages=281–282 |last2=Ninov |first2=V. |last3=Heßberger |first3=F. P. |last4=Armbruster |first4=P. |last5=Folger |first5=H. |last6=Münzenberg |first6=G. |last7=Schött |first7=H. J. |last8=Popeko |first8=A. G. |last9=Yeremin |first9=A. V. |last10=Andreyev |first10=A. N. |last11=Saro |first11=S. |last12=Janik |first12=R. |last13=Leino |first13=M. |bibcode = 1995ZPhyA.350..281H |issue=4 |display-authors=8}}
16. ^{{Cite journal |doi=10.1140/epja/i2001-10119-x |title=New results on elements 111 and 112 |year=2002 |last=Hofmann |first=S. |journal=The European Physical Journal A |volume=14 |pages=147–157 |last2=Heßberger |first2=F. P. |last3=Ackermann |first3=D. |last4=Münzenberg |first4=G. |last5=Antalic |first5=S. |last6=Cagarda |first6=P. |last7=Kindler |first7=B. |last8=Kojouharova |first8=J. |last9=Leino |first9=M. |last10=Lommel |first10=B. |last11=Mann |first11=R. |last12=Popeko |first12=A.G. |last13=Reshitko |first13=S. |last14=Śaro |first14=S. |last15=Uusitalo |first15=J. |last16=Yeremin |first16=A.V. |issue=2 |display-authors=8}}
17. ^1 {{cite journal |last1=Morita |first1=K. |last2=Morimoto |first2=K. K. |last3=Kaji |first3=D. |last4=Goto |first4=S. |last5=Haba |first5=H. |last6=Ideguchi |first6=E. |last7=Kanungo |first7=R. |last8=Katori |first8=K. |last9=Koura |first9=H. |last10=Kudo |first10=H. |last11=Ohnishi |first11=T. |last12=Ozawa |first12=A. |last13=Peter |first13=J. C. |last14=Suda |first14=T. |last15=Sueki |first15=K. |last16=Tanihata |first16=I. |last17=Tokanai |first17=F. |last18=Xu |first18=H. |last19=Yeremin |first19=A. V. |last20=Yoneda |first20=A. |last21=Yoshida |first21=A. |last22=Zhao |first22=Y.-L. |last23=Zheng |first23=T. |title=Status of heavy element research using GARIS at RIKEN |year=2004 |journal=Nuclear Physics A |volume=734 |pages=101–108 |doi=10.1016/j.nuclphysa.2004.01.019|bibcode=2004NuPhA.734..101M }}
18. ^{{Cite journal |doi=10.1103/PhysRevLett.93.212702 |title=Development of an Odd-Z-Projectile Reaction for Heavy Element Synthesis: 208Pb(64Ni,n)271Ds and 208Pb(65Cu,n)272111 |year=2004 |author=Folden, C. M. |journal=Physical Review Letters |volume=93 |pages=212702 |pmid=15601003 |issue=21 |bibcode=2004PhRvL..93u2702F |last2=Gregorich |first2=K. |last3=Düllmann|first3=Ch.|last4=Mahmud|first4=H.|last5=Pang|first5=G.|last6=Schwantes|first6=J.|last7=Sudowe|first7=R.|last8=Zielinski|first8=P.|last9=Nitsche|first9=H.|last10=Hoffman|first10=D.|url=http://repositories.cdlib.org/cgi/viewcontent.cgi?article=2704&context=lbnl|display-authors=8}}
19. ^1 {{cite web |url=http://www.physics.adelaide.edu.au/cssm/workshops/inpc2016/talks/Morimoto_Mon_HallL_0930.pdf |title=The discovery of element 113 at RIKEN |last=Morimoto |first=Kouji |date=2016 |website=www.physics.adelaide.edu.au |publisher=26th International Nuclear Physics Conference |access-date=14 May 2017}}
20. ^1 2 {{cite journal|last1=Oganessian |first1=Yuri Ts.|last2=Abdullin |first2=F. Sh.|last3=Bailey |first3=P. D.|last4=Benker |first4=D. E.|last5=Bennett |first5=M. E.|last6=Dmitriev |first6=S. N.|last7=Ezold |first7= J. G.|last8=Hamilton |first8= J. H.|last9=Henderson |first9= R. A. |title=Synthesis of a New Element with Atomic Number Z=117 |date=2010-04-09 |journal=Physical Review Letters |volume=104 |number=142502 |doi=10.1103/PhysRevLett.104.142502 |pmid=20481935 |bibcode=2010PhRvL.104n2502O |url=https://www.researchgate.net/publication/44610795 |displayauthors=3 |pages=142502}}
21. ^1 2 {{cite book|doi=10.1063/1.2746600|chapter=Heaviest Nuclei Produced in 48Ca-induced Reactions (Synthesis and Decay Properties)|title=AIP Conference Proceedings|year=2007|last1=Oganessian|first1=Yu. Ts.|last2=Penionzhkevich|first2=Yu. E.|last3=Cherepanov|first3=E. A.|volume=912|pages=235–246}}
22. ^1 {{cite journal|title=Experiment on the Synthesis of Element 113 in the Reaction 209Bi(70Zn,n)278113|year=2004|journal=Journal of the Physical Society of Japan|volume=73|issue=10|pages=2593–2596|doi=10.1143/JPSJ.73.2593|bibcode=2004JPSJ...73.2593M|last1=Morita|first1=Kosuke|last2=Morimoto|first2=Kouji|last3=Kaji|first3=Daiya|last4=Akiyama|first4=Takahiro|last5=Goto|first5=Sin-ichi|last6=Haba|first6=Hiromitsu|first7=Eiji |last7=Ideguchi|first8=Rituparna |last8=Kanungo|first9=Kenji |last9=Katori|first10=Hiroyuki |last10=Koura|first11=Hisaaki |last11=Kudo|first12=Tetsuya |last12=Ohnishi|first13=Akira |last13=Ozawa|first14=Toshimi |last14=Suda|first15=Keisuke |last15=Sueki|first16=HuShan |last16=Xu|first17=Takayuki |last17=Yamaguchi|first18=Akira |last18=Yoneda|first19=Atsushi |last19=Yoshida|first20=YuLiang |last20=Zhao}}
23. ^{{cite web|url=http://www.nndc.bnl.gov/chart/reCenter.jsp?z=111&n=170|title=Interactive Chart of Nuclides|publisher=Brookhaven National Laboratory |last=Sonzogni |first=Alejandro |location=National Nuclear Data Center |accessdate=2008-06-06}}
24. ^1 2 3 {{cite journal|last=Feng|first=Z.|last2=Jin|first2=G.|last3=Li|first3=J.|title=Production of new superheavy Z=108-114 nuclei with 238U, 244Pu and 248,250Cm targets|date=2009|arxiv=0912.4069|journal=Physical Review C|volume=80|issue=5|pages=057601|doi=10.1103/PhysRevC.80.057601}}

Notes

  • Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
  • Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC, which use expanded uncertainties.

Isotopes and nuclear properties

Nucleosynthesis

Super-heavy elements such as roentgenium are produced by bombarding lighter elements in particle accelerators that induce fusion reactions. Whereas the lightest isotope of roentgenium, roentgenium-272, can be synthesized directly this way, all the heavier roentgenium isotopes have only been observed as decay products of elements with higher atomic numbers.[12]

Depending on the energies involved, fusion reactions can be categorized as "hot" or "cold". In hot fusion reactions, very light, high-energy projectiles are accelerated toward very heavy targets (actinides), giving rise to compound nuclei at high excitation energy (~40–50 MeV) that may either fission or evaporate several (3 to 5) neutrons.[13] In cold fusion reactions, the produced fused nuclei have a relatively low excitation energy (~10–20 MeV), which decreases the probability that these products will undergo fission reactions. As the fused nuclei cool to the ground state, they require emission of only one or two neutrons, and thus, allows for the generation of more neutron-rich products.[12] The latter is a distinct concept from that of where nuclear fusion claimed to be achieved at room temperature conditions (see cold fusion).[14]

The table below contains various combinations of targets and projectiles which could be used to form compound nuclei with Z=111.

Target Projectile CN Attempt result
205Tl70Zn275RgFailure to date}}
208Pb65Cu273RgSuccessful reaction}}
209Bi64Ni273RgSuccessful reaction}}
231Pa48Ca279RgReaction yet to be attempted}}
238U41K279RgReaction yet to be attempted}}
244Pu37Cl281RgReaction yet to be attempted}}
248Cm31P279RgReaction yet to be attempted}}
250Cm31P281RgReaction yet to be attempted}}

Cold fusion

Before the first successful synthesis of roentgenium in 1994 by the GSI team, a team at the Joint Institute for Nuclear Research in Dubna, Russia, also tried to synthesize roentgenium by bombarding bismuth-209 with nickel-64 in 1986. No roentgenium atoms were identified. After an upgrade of their facilities, the team at GSI successfully detected 3 atoms of 272Rg in their discovery experiment.[15] A further 3 atoms were synthesized in 2002.[16] The discovery of roentgenium was confirmed in 2003 when a team at RIKEN measured the decays of 14 atoms of 272Rg.[17]

The same roentgenium isotope was also observed by an American team at the Lawrence Berkeley National Laboratory (LBNL) from the reaction:

{{nuclide|lead|208}} + {{nuclide|copper|65}} → {{nuclide|roentgenium|272}} + {{SubatomicParticle|neutron}}

This reaction was conducted as part of their study of projectiles with odd atomic number in cold fusion reactions.[18]

The 205Tl(70Zn,n)274Rg reaction was tried by the RIKEN team in 2004 and repeated in 2010 in an attempt to secure the discovery of its parent 278Nh:[19]

{{nuclide|thallium|205}} + {{nuclide|zinc|70}} → {{nuclide|roentgenium|274}} + {{SubatomicParticle|neutron}}

Due to the weakness of the thallium target, they were unable to detect any atoms of 274Rg.[19]

As decay product

List of roentgenium isotopes observed by decay
Evaporation residue Observed roentgenium isotope
294Lv, 290Fl, 290Nh ?286Rg ?
299Ubn, 295Og, 291Lv, 287Fl, 287Nh ?283Rg ?
294Ts, 290Mc, 286Nh282Rg[20]
293Ts, 289Mc, 285Nh281Rg[20]
288Mc, 284Nh280Rg[21]
287Mc, 283Nh279Rg[21]
282Nh278Rg[21]
278Nh274Rg[22]

All the isotopes of roentgenium except roentgenium-272 have been detected only in the decay chains of elements with a higher atomic number, such as nihonium. Nihonium currently has seven known isotopes; all of them undergo alpha decays to become roentgenium nuclei, with mass numbers between 274 and 286. Parent nihonium nuclei can be themselves decay products of flerovium, moscovium, livermorium, tennessine, and (unconfirmed) oganesson or unbinilium. To date, no other elements have been known to decay to roentgenium.[23] For example, in January 2010, the Dubna team (JINR) identified roentgenium-281 as a final product in the decay of tennessine via an alpha decay sequence:[20]

{{nuclide|tennessine|293}} → {{nuclide|moscovium|289}} + {{nuclide|helium|4}}

{{nuclide|moscovium|289}} → {{nuclide|nihonium|285}} + {{nuclide|helium|4}}

{{nuclide|nihonium|285}} → {{nuclide|roentgenium|281}} + {{nuclide|helium|4}}

Nuclear isomerism

274Rg

Two atoms of 274Rg have been observed in the decay chain of 278Nh. They decay by alpha emission, emitting alpha particles with different energies, and have different lifetimes. In addition, the two entire decay chains appear to be different. This suggests the presence of two nuclear isomers but further research is required.[22]

272Rg

Four alpha particles emitted from 272Rg with energies of 11.37, 11.03, 10.82, and 10.40 MeV have been detected. The GSI measured 272Rg to have a half-life of 1.6 ms while recent data from RIKEN have given a half-life of 3.8 ms. The conflicting data may be due to nuclear isomers but the current data are insufficient to come to any firm assignments.[15][17]

Chemical yields of isotopes

Cold fusion

The table below provides cross-sections and excitation energies for cold fusion reactions producing roentgenium isotopes directly. Data in bold represent maxima derived from excitation function measurements. + represents an observed exit channel.

ProjectileTargetCN1n2n3n
64Ni209Bi273Rg3.5 pb, 12.5 MeV
65Cu208Pb273Rg1.7 pb, 13.2 MeV

Theoretical calculations

Evaporation residue cross sections

The below table contains various targets-projectile combinations for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given.

DNS = Di-nuclear system; σ = cross section

Target Projectile CN Channel (product) σmax Model Ref
238U41K279Rg4n (275Rg)0.21 pbDNS[24]
244Pu37Cl281Rg4n (277Rg)0.33 pbDNS[24]
248Cm31P279Rg4n (277Rg)1.85 pbDNS[24]
250Cm31P281Rg4n (277Rg)0.41 pbDNS[24]

References

  • Isotope masses from:
    • {{cite journal |author=M. Wang |author2=G. Audi |author3=A. H. Wapstra |author4=F. G. Kondev |author5=M. MacCormick |author6=X. Xu|year=2012 |title=The AME2012 atomic mass evaluation (II). Tables, graphs and references. |url=http://amdc.in2p3.fr/masstables/Ame2012/Ame2012b-v2.pdf |journal=Chinese Physics C |volume=36 |issue= 12 |pages=1603–2014 |doi=10.1088/1674-1137/36/12/003|bibcode = 2012ChPhC..36....3M |display-authors=etal}}
    • {{NUBASE 2003}}
  • Isotopic compositions and standard atomic masses from:
    • {{CAWIA 2003}}
    • {{CIAAW 2005}}
  • Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
    • {{NUBASE 2003}}
    • {{NNDC}}
    • {{CRC85|chapter=11}}
    • {{cite journal|author=Yu. Ts. Oganessian |title=Heaviest nuclei from 48Ca-induced reactions |url=http://www.iop.org/EJ/abstract/0954-3899/34/4/R01/ |journal=Journal of Physics G |year=2007 |volume=34 |issue=4 |pages=R165–R242|bibcode = 2007JPhG...34..165O |doi = 10.1088/0954-3899/34/4/R01 }}
{{Navbox element isotopes}}

3 : Roentgenium|Isotopes of roentgenium|Lists of isotopes by element
随便看

　

开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。

　

Copyright © 2023 OENC.NET All Rights Reserved
京ICP备2021023879号 更新时间：2024/9/21 1:42:09