Fat Silicon Atoms Are Doubly Magic

[zavvy]

<b>Fat Silicon Atoms Are Doubly Magic</b><br /><br />LINK<br /><br />A form of silicon that is bloated with extra neutrons has revealed a 'magic number' for the protons in its nucleus.<br /><br />Atomic nuclei are only stable when packed with certain combinations of positive protons and uncharged neutrons. Some combinations are more stable than others, and the numbers of protons or neutrons in such cases are called 'magic'. This extra stability is achieved when the subatomic particles fill up certain energy levels within the nuclei, leaving no stray particles hanging around at higher energies.<br /><br />Physicists have long known of a series of such magic numbers, including 2, 8, 20, 28, 50, 82 and 126. Some elements have quantities of subatomic nuclei that match these numbers and are more stable. Some even hit these scores in both their neutrons and protons, making them doubly magic (see 'Double bind'). <br /><br />But not every magic number is detailed in a textbook; researchers are still finding more. This week, a team of US and British scientists report in Nature1 that radioactive silicon-42, an artificial element with 14 protons and 28 neutrons, also seems to be doubly magic. <br /><br />"Between 8 and 20 there are some energy sublevels," explains Jeff Tostevin, a theoretical nuclear physicist from the University of Surrey, UK, who was part of the team. "Normally, these sublevels are very close together, so they don't obviously stand out as a magic number," he explains. This is the case in the most common form of silicon, which has 14 protons and 14 neutrons.<br /><br />But nuclei grow and change shape as more subatomic particles are packed in, and this changes the relative location of their energy levels. Paul Cottle, a nuclear physicist from Florida State University, Tallahassee, and the rest of the study's international team had reason to believe that as silicon gets beefed up with neut

 

[silylene old]

That is an interesting article. I am surprised that the number of neutrons in a 'fat' Si atom was actually doubled to 28!<br /><br />Natural silicon contains 92.2% of the isotope 28, 4.7% of silicon 29 and 3.1% of silicon 30. Different numbers of neutrons can have interesting characteristics......Interestingly, pure Si-28 has about twice the thermal conductivity of natural silicon. This can be exploited in a commercially useful manner: if a wafer of pure Si-28 is used to make an integrated circuit, the resulting computer chip is easier to cool and prevent overheating.<br /><br />The company Isonics is attempting to exploit the improved thermal characteristics of pure 28-Si. Some interesting stuff: www.isonics.com <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[emperor_of_localgroup]

Fat Si? How do they make Si with 28 neutrons? Its not a natural isotope. I thought isotopes are common only in heavier atoms. That article also talks about oxygen with 16 neutrons (O-24). Cant wait to see the some practical applications of these fat elements. Who says we cant change the nature? <div class="Discussion_UserSignature"> <font size="2" color="#ff0000"><strong>Earth is Boring</strong></font> </div>

 

[zavvy]

<font color="yellow">How do they make Si with 28 neutrons?</font><br /><br />They're very clever modern day alchemists...

 

[valareos]

so 200 NS is stable?

 

[emperor_of_localgroup]

No, I was asking how do they attach extra 14 neutrons to a normal Si atom? by bombardment or by chemical reaction? <br /><br />Steve: Only 200 ns? Here goes my plan to build a fat computer with some fat Si chips. But I dont know what it would be like to breathe O-24 instead of O-16. <div class="Discussion_UserSignature"> <font size="2" color="#ff0000"><strong>Earth is Boring</strong></font> </div>

 

[valareos]

"To test this idea, the team fired a high-energy beam of sulphur-44 at a beryllium target. This forced the sulphur nuclei to lose two protons, transmuting them to silicon. They counted how much silicon-42 was produced by the collisions, and compared this with quantum mechanical calculations that assumed 14 was magic. The numbers matched up perfectly, says Tostevin."<br /><br /><br />Bombardment. Its amazing how us humans can create things nature abhors. Like the vaccuum...