Photoelectron spectroscopy PES, UPS, XPS, ESCA

the diffraction data mainly provide informatirHi about intramolecular braid parameters. 

Results of electton diffraction data for BCI3 give bonded B-Cl distances of 174 pm (all bonds of equal length) and non-bonded Q...C1 distances of 301 pm (three equal distances). Show that these data are consistent with BCI3 being trigonal planar rather than trigonal pyramidal. 

Electron diffraction is not confined to the study of gases. Low-energy electrons (10-200eV) are diffracted from the surface of a soUd and the diffraction pattern so obtained provides information about the arrangement of atoms on the surface of the solid. 

Structural data are stored in, and can be accessed from, three primary databases which are continually updated. Data for organic and metal-organic compounds and boranes are compiled by the Cambridge Structural Database (www.ccdc. cam.ac.uk), while crystallographic data for purely inorganic compounds (e.g. metal and non-metal halides and oxides) are deposited in the Inorganic Crystal Structure Database (www.fiz-karlsruhe.de). Structural data for biological macromolecules are collected in the Protein Data Bank (www.rcsb.org/pdb). 

Photoelectron spectroscopy (PES) is a technique used to study the energies of occupied atomic or molecular orbitals. 

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