A series of JAVA applets of Tanbe-Sugano diagrams were developed by Prof. Robert Lancashire at the University of the West Indies. These diagrams allow students to determine deltao/B values based on ratios of peak energies without the pain of rulers and drawing lines. There are also features that allow a person to input values and automatically calculate certain parameters. You can also quickly find values of delta_o and B for certain complexes via a drop-down menu on some of the pages (e.g. Cr3+ complexes).
Students will be able to interpret absorption spectra using the provided Tanabe-Sugano diagram applets.
I use these applets when teaching Tanabe-Sugano diagrams in my class and students get significant practice with the applets through homework assignments and a lab experiment.
Note that you cannot use Chrome (Firefox or Internet Explorer both work) and you will likely need to add the website to your "safe" list in your JAVA settings in order for the applets to work.