Finding Molecules with Specific Colors Using Molecular Annealing

Many quantum chemical programs can calculate the properties of a molecule from its structure but the reverse question, identifying a compound that has a specific set of properties, is a much more difficult problem because the solution space is vast and the variables are discrete rather than continuous. One way to approach this problem is to perform an elaborate trial-and-error search through an enormous collection of potential candidates. Another way is to use an optimization algorithm to sort through a set of potential molecules. These methods generally arrange a set of basic building blocks (atoms, chemical groups, etc.) using combinatorial method, simulated annealing or genetic algorithms. Any optimization algorithm that wants to find molecules with specific properties must be able to represent the structure of a molecule in a form that a program can easily manipulate.

In this poster, we show that simulated annealing can find molecules that have specific optical absorption peaks. It does this by calculating both the molecular excitation enegies and the oscillator strenghts for each molecular candidate. Those molecules that have absorption peaks close to the desired values become the start of the next step in the simulating annealing algorithm.