Lorraine A. Malaspina, Erna K. Wieduwilt, Justin Bergmann, Florian Kleemiss, Benjamin Meyer, Manuel F. Ruiz-López, Rumpa Pal, Emanuel Hupf, Jens Beckmann, Ross O. Piltz, Alison J. Edwards, Simon Grabowsky, Alessandro Genoni
Journal of Physical Chemistry Letters (2019), Volume 10, Issue 22, 21 November 2019, Pages 6973-6982
The coupling of the crystallographic refinement technique Hirshfeld atom refinement (HAR) with the recently constructed libraries of extremely localized molecular orbitals (ELMOs) gives rise to the new quantum-crystallographic method HAR-ELMO. This method is significantly faster than HAR but as accurate and precise, especially concerning the free refinement of hydrogen atoms from X-ray diffraction data, so that the first fully quantum-crystallographic refinement of a protein is presented here. However, the promise of HAR-ELMO exceeds large molecules and protein crystallography. In fact, it also renders possible electron-density investigations of heavy elements in small molecules and facilitates the detection and isolation of systematic errors from physical effects.