Isolated proton emission was eventually observed in some elements.

It decays by proton emission to helium-3 with half-life of about 10 seconds.

Research in the field flourished after this breakthrough, and to date more than 25 isotopes have been found to exhibit proton emission.

Beyond the proton drip line along the upper left, nuclides decay by proton emission.

There are 13 known isotopes of boron, the shortest-lived isotope is which decays through proton emission and alpha decay.

The shortest-lived known isotope of lithium is lithium-4 which decays by proton emission with a half-life of about 7.6x10 seconds.

The abundant oxygen-16 nucleus, for example, undergoes neutron activation, rapidly decays by a proton emission forming nitrogen-16, which decays to oxygen-16.

Proton emission (also known as proton radioactivity) is a type of radioactive decay in which a proton is ejected from a nucleus.

Proton emission is not seen in naturally occurring isotopes; proton emitters can be produced via nuclear reactions, usually utilising some kind of particle accelerator.

The study of proton emission has aided the understanding of nuclear deformation, masses and structure, and it is a wonderfully pure example of quantum tunneling.

While most of germanium's radioisotopes decay by beta decay, Ge and Ge decay by β delayed proton emission.

Most isotopes of thulium lighter than 169 atomic mass units decay via electron capture or β+ decay, although some exhibit significant alpha decay or proton emission.

This first step is extremely slow, because the beta-plus decay of the diproton to deuterium is extremely rare (the vast majority of the time, it decays back into hydrogen-1 through proton emission).

As a consequence, there are no naturally occurring nuclei on Earth which undergo proton emission or neutron emission; however, such nuclei can be created, for example, in the laboratory with accelerators or naturally in stars.

The unpredictable composition of the products (which vary in a broad probabilistic and somewhat chaotic manner) distinguishes fission from purely quantum-tunnelling processes such as proton emission, alpha decay and cluster decay, which give the same products each time.

The middle chalcogens (selenium and tellurium) have similar decay tendencies as the lighter chalcogens, but their isotopes do not undergo proton emission and some of the most neutron-starved isotopes of tellurium undergo alpha decay.

For example, if one wishes to ask if C, the most common isotope of carbon, can undergo proton emission to B, one finds that about 16 MeV must be added to the system for this process to be allowed.

Nb, Nb, and Nb have minor β delayed proton emission decay paths, Nb decays by electron capture and positron emission, and Nb decays by both β and β decay.

Isotopes with masses below 191 decay by some combination of β decay, α decay, and proton emission, with the exceptions of Ir, which decays by electron capture, and Ir, which decays by positron emission.

The least stable is Au, which decays by proton emission with a half-life of 30 s. Most of gold's radioisotopes with atomic masses below 197 decay by some combination of proton emission, α decay, and β+ decay.

Among the lighter chalcogens (oxygen and sulfur), the most neutron-starved isotopes undergo proton emission, the moderately neutron-starved isotopes undergo electron capture or β+ decay, the moderately neutron-rich isotopes undergo β- decay, and the most neutron rich isotopes undergo neutron emission.