EPR simulator is under construction! Proceed with care!

Currently available simulations

Why do I need the EPR simulator?

This site was designed to show simulated EPR spectra in an interactive way: the spectrum is continuously updated as the parameters are changed. The main aim is to illustrate how different parameters affect EPR spectra. The examples were carefully chosen to show commonly-observed features and typical spectral shapes. The range of parameters is restricted to reasonable values, and care was taken not to produce wrong or impossible spectra. The simulator can be used to:

Compatibility and known issues

This site assumes some knowledge of EPR spectroscopy. Each simulator page has a "What can I learn on this page?" menu which takes you through several important points for each type of spectra.

Each page has question marks (?) that bring up tooltips with help. All dialogs (like this one) can be resized, moved around on the page, and minimised and closed.

The simulator is very interactive, you can change the parameters continuously (e.g., by dragging the sliders or keeping the up/down icons pressed with the mouse) and the spectrum will be updated in real time. The spectrum display has powerful features: you can zoom in/out, save spectra to overlap with other spectra, measure distances between peaks etc - all these features make the simulator as interactive as possible. You should experiment with the spectra by changing various parameters!

However, you will learn nothing by just randomly changing parameters. Make sure you understand the meaning of parameters you are changing, and do not change parameters you do not understand.

Simulation of EPR spectra is not that easy! In particular, anisotropic spectra are very difficult to simulate and the simulations often take long time. To get round this problem, hundreds of thousands of different EPR spectra have been simulated in advance and uploaded to the server. Every time you simulate a spectrum, a small file with the spectrum data is downloaded from the server (one spectrum is only 1 kB so the download is fast and internet traffic stays reasonably low).

The isotropic spectra, on the other hand, are relatively easy to simulate. These spectra are calculated by your browser. Care was taken to make the simulations fool-proof, e.g., integral values and peak intensities are reproduced accurately even for extremely sharp peaks when the peak width is smaller than the distance between adjacent data points on the spectrum.

The code for the simulator was written by Victor Chechik at the University of York. The idea to develop the simulator was borne out of discussions with Damien Murphy and Emma Carter at the University of Cardiff.

Most anisotropic spectra were simulated using EasySpin.

Many colleagues have helped to shape the simulator, choose the best examples and reasonable range of parameters. The simulator would have been impossible without their input.

You can help too - please email Victor at victor.chechik"at"york.ac.uk with any suggestions on new simulations, new parameters to add to existing simulations, any errors or potential improvements.

Last update 14 April 2016