Matrices referencing element

The individual elements of a matrix are often referenced as scalars, with subscripts referring to the row and column hence, in the matrix above, y2i = 6 which is the element in row 2 and column 1. 

CpWIr3(CO)n was prepared as previously described (2). Diphenylacetylene (Aldrich) was used as received. Preparative thin-layer chromatography was carried out on (20 x 20 cm) silica gel Si250F plates (J.T. Baker). Infrared spectra were recorded on a Perkin-Elmer 1750 FT-IR spectrophotometer. H NMR (360 MHz) spectra were obtained on a Nicolet NT-360 spectrometer. Fast atom bombardment (FAB) mass spectra were obtained by the staff of the Mass Spectrometry Laboratory of the School of Chemical Sciences on a VG ZAB-SE mass spectrometer, using a matrix of dithioerythritol/dithiothieitol calculated masses are referenced to 184W and 193Ir. Elemental analyses were performed by the School Microanalytical Laboratory. 

To consider the specific selection rules on electric dipole (El) transitions in one-electron atoms, we evaluate the matrix elements of the pertinent electric dipole moment operator p = Sj e,r,- = Zer — er, where tff and r are the positions of the nucleus and electron referenced to an arbitrary origin in space. Then... 

Notice how each element in A is referenced the name of the matrix followed by two parentheses bracketin he wojndice orjhatparticula le ... 

Using these expressions, we may rewrite the expiession for the generalized Fock matrix in (10.8.23) such that only density-matrix elements with all indices active are referenced. Keeping in mind that the generalized Fock matrix is not symmetric, we begin by calculating the elements of the generalized Fock matrix where the first index is inactive and the second is unspecified... 

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