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Gah, I mixed up atomic mass and atomic number in that equation. Anyway...

Looking at the isotopes of Ca, Sc ad Ti, the observed transmutation looks definitely _special_.

Let's see... 40Ca is by far the most common Calcium isotope, but its atomic weight is way too low to support the transmutation to Titanium, as

Naturally occurring titanium (Ti) is composed of 5 stable isotopes; 46Ti, 47Ti, 48Ti, 49Ti and 50Ti with 48Ti being the most abundant (73.8% natural abundance).
(wikipedia)

Now, for Calcium

There are five observationally stable isotopes (40Ca, 42Ca, 43Ca, 44Ca and 46Ca), plus one isotope (48Ca) with such a long half-life that for all practical purposes it can be considered stable.
Although 40Ca is the most abundant isotope by far, only 44Ca, 46Ca and 48Ca can result in stable Titanium isotopes by Deuterium absorption followed by beta decay. 44Ca, with a natural abundance of a couple percent, would seem like the only suitable candidate.

The intermediate states would have to be 46Sc, 48Sc or 50Sc respectively, and given that

The isotopes of scandium range in atomic weight from 36 u (36Sc) to 60 u (60Sc). The primary decay mode at masses lower than the only stable isotope, 45Sc, is Beta-plus or electron capture, and the primary mode at masses above it is beta-minus. The primary decay products at atomic weights below 45Sc are calcium isotopes and the primary products from higher atomic weights are titanium isotopes.
it would seem to fit.

Now let's look at the energy balance. The isotopic masses of the Calcium and Titanium isotopes are (in atomic units):

Calcium    Titanium   Difference
43.9554818 45.9526316 1.9971498 
45.9536926 47.9479463 1.9942537
47.952534  49.9447912 1.9922572

while the mass of Deuterium is 2.01410178. The smallest energy release would be from the
44Ca -> 46Ti
reaction. The energy difference is 0.01695198u. The electron rest mass is 0.0005486u, so almost the entire energy difference would be released: 0.0164034u or 15MeV. That's a lot of energy...

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by Migeru (migeru at eurotrib dot com) on Sat Jan 12th, 2013 at 02:30:17 PM EST
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