You're thinking of Deuterium-He3 fusion. It produces less energy than D-D, but the reaction is aneutronic - all the byproducts are charged particles (allowing for the possibility of direct conversion to electricity which may be more efficient than thermal conversion), no neutrons. My understanding is that a D-He3 reaction would have a higher activation ebergy.
As far as maximizing energy production, afaik a deuterium-tritium reaction his the sweet spot, producing significantly (a factor of 3 or 4?) more energy than a D-D reaction. Theoretically, we can breed tritium from lithium in a D-D reactor - this is one of the things being investigated at ITER.
Personally, I think we're about as likely to terraform Mars as we are Venus - although its 2 moons could be ideal to hollow out and transform into floating cities - or even interstellar spacecraft (multi-generation craft if we can't figure out how to build a relativistic one).
If you want to explore such concepts (among many others) more in depth, check out Night's Dawn and the Greg Mandel trilogy by Peter F. Hamilton and Revelation Space by Alastair Renolds.
I am not much into atomic physics right now, so I don't read books on it. I just google any questions I have. This is where I heard of the He-3 to He-3 fusion which consumes 1 kW to give 1mW of power, and hence it's not feasible as of now, but CERN is working on it. https://www.technologyreview.com/s/408558/mining-the-moon/amp/
I was suggesting scifi novels, not books on physics.
Damn, lol. I have exams now. I'll enjoy the novels once I'm free.