Hi I am looking at strontium, and I wish to find the difference in energy between the 1S0-1P1 transition (~ 461nm) in Sr-88 and Sr-86. I don't need to calculate it, I need to look it up in a table. I thought that NIST would be helpful (http://physics.nist.gov/PhysRefData/ASD/lines_form.html), but I didn't get anything useful from there. Most likely it is because I don't know how to use it properly. When I type in Sr, I get all the ions (Sr I, Sr II, ...). How do I know which one Sr-88 and Sr-86 is? Best wishes, Niles.