In reply to Jones Beene's message of Wed, 24 Apr 2013 19:07:24 -0700: Hi, [snip] >Actually The neutron has mass slightly larger than that of a proton: >939.565378 MeV compared to 938.272046 MeV. Consequently, a deuteron has >slightly more mass than a diproton. > >That is one of the many reasons why the reaction on the Sun, the one that >results in a deuteron is extraordinarily rare. It is basically endothermic. >
The mass of two protons is 2.014552933 amu. The mass of a deuteron is 2.01355362 amu. Note that the deuteron is actually lighter than the two protons. IOW this reaction is exothermic. It is this mass difference that is responsible for deuterium being bound. Bound nucleons weigh less than free particles, and the amount by which they weigh less varies with the nucleus they are in. Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
