The ability to accurately and efficiently study the absorption spectra of large chemical systems necessitates the development of new algorithms and the use of different architectures. We have developed a highly parallelizable algorithm in order to study excited state properties with ab initio electronic structure theory. This approach has recently been implemented to take advantage of graphical processing units to further improve efficiency. This method will be applied to characterize the absorption of the proactive yellow protein, one of the primary models for studying photoreceptor proteins.
