EasySpyn (EasySpyn): EasySpin's EPR simulators in Python

A Python port of EasySpin, the MATLAB toolbox for EPR spectral simulation by Stefan Stoll and co-workers (MIT licence), keeping EasySpin's interface: spin systems as dictionaries with EasySpin's field names, fields in mT, couplings in MHz, 1-based spin numbers.

pip install easyspyn
pip install "easyspyn[fast]"  # adds Numba for the line-summation and projection kernels

import easyspyn as es

nitroxide = {"g": [2.0088, 2.0061, 2.0027], "Nucs": "14N", "A": [16, 16, 86], "lwpp": 0.3}
powder = es.pepper(nitroxide, {"mwFreq": 9.5, "Range": [330, 350], "nPoints": 1024})
print(powder.x.shape, powder.spec.shape)

What is ported: pepper and garlic (cw EPR of powders, crystals and solutions), esfit (fitting), salt and endorfrq (ENDOR), curry (magnetometry), chili (slow motion), saffron (pulse EPR: ESEEM, HYSCORE, Mims ENDOR), and the foundation underneath (sop, ham, levels, resfields, line shapes, grids). Results are compared with EasySpin 6.0.15's own output on about 280 reference cases. Not ported: saffron's thyme engine and spidyan, the GUIs, and some options; the guide lists them.

EasySpyn is part of the Spynach project, which also ports the Spinach spin dynamics kernel. It is an early release (0.3.0); corrections and bug reports are welcome on GitHub.

• Guides: https://github.com/ajerschow/spynach/blob/main/docs/easyspyn.md
• Differences from EasySpin: https://github.com/ajerschow/spynach/blob/main/docs/coming-from-easyspin.md
• Try it in the browser, with timings against EasySpin: https://ajerschow.github.io/spynach/easyspin.html

Attribution: EasySpyn is a translation of EasySpin and keeps its notice; see LICENSE. Each function's docstring names the EasySpin contributors to the original file (help(easyspyn.pepper)); the full table is at https://github.com/ajerschow/spynach/blob/main/docs/easyspin-credits.md.