Almost two months after graduation, Letty Black has received a late graduation present: becoming a published author. Her computational work with Professor Marmorino was just published in the Journal of Mathematical Chemistry in an 'Online First' format before being assigned to a particular volume of the print journal. Letty worked with Marmorino during the summer of 2015 between her junior and senior years. Their research generalized an old formula (scalar version) that computes lower bounds to the expectation values of positive operators to a matrix method, hence the title: Lower bounds to the ground-state expectation value of non-negative operators. Essentially this means that they improved on a method to calculate HALF of an error bar (just the LOWER bound) to properties such as the average distance (always positive) of an atom's electron(s) from the nucleus. Such a distance varies with the state of the atom - for example the 1s state of the hydrogen atom keeps the electron close to the nucleus but a 4d state of the hydrogen atom keeps the electron much further on average. Only for the hydrogen atom are these distances known exactly; for all other atoms we have only estimates from theory. Congratulations to Letty on her publication!
