Conversely, a theoretical vantage is limited by the level of theory used, but allows for an opportunity to estimate photophysical properties well before synthesis, and for distinguishability and separability of mechanisms. A good example of this can be found in density functional theory-based excited state exciton dynamics where each mechanism can be was calculated individually and later recombined for various quantum yeilds of excited states . Due to the difficulty associated with experimental measurement , it is sometimes considered more prudent to employ ab initio techniques. However, the strength of theory is also it's weakness: it is only as accurate as the level of theory used.