First spectrum of tin

The spectrum emitted by neutral tin atoms has been measured, compiled, and analyzed. Revised wavelengths and relative intensities are given for 378 lines, 341 of which were observed photographically (1697.59 to 12536.5 A), and 37 of greater wavelengths (12788.2 to 24738.2 A) were measured radiometrically by Randall and Wright. About 80 percent of these lines are classified as combinations of energy levels arising from 15p2, 5pns, 5pnp, 5pnd, and 5pnf electron configurations. The average difference between observed and computed wave numbers for lines measured photographically is 0.09 cm-I Four series of the type 5p2-5pns yield a mean absolute value of 59155 cm-I for the ground level, 5p2. sPa, of neutral tin atoms. From this, the principal ionization potential of tin is calculated to be 7.297 volts.