In nuclear fusion, the atoms used to produce helium with larger masses are deuterium (D) and tritium (T).

Here's the reaction:

D + T → ⁴He + n + 17.6 MeV

* Deuterium (D) is a heavy isotope of hydrogen with one proton and one neutron.

* Tritium (T) is a radioactive isotope of hydrogen with one proton and two neutrons.

* ⁴He is a helium nucleus (alpha particle) with two protons and two neutrons.

* n is a neutron.

* 17.6 MeV is the energy released in the reaction.

This reaction is known as the deuterium-tritium (D-T) fusion reaction and is the most common fusion reaction used in research and development. It's the basis for current experimental fusion reactors like ITER.

Important Note: While other fusion reactions can produce helium, they require higher temperatures and pressures and are less efficient than the D-T reaction.