Chemists often label orbital energies with the lower case Greek letter epsilon, . For the H atom there is no distinction between E and . However, be forewarned that for multielectron atoms it will be important to make such a distinction. The only variable in this equation is r, the distance between the electron and the proton. Since in atomic units the value of a 0 is 1, we normally do not explicitly exhibit it in the equation.
Chemists usually refer to the wave function of the H atom as the atomic orbital of the atom.
For the ground state it is given the symbol 1s. We now consider how to interpret this mathematical function. The sum of these probability densities over all space gives the total probability of finding the electron, and this number must be one. There are two common ways to graph the wave function. Because of our interest in the square of the wave function and its relationship to probability we will present plots that involve 2 .