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The seventh spectrum of barium (Ba VII) has been investigated using experimental recordings made on a 3-m normal incidence vacuum spectrograph in Canada in the wavelength region 300–2000 A. The data below 350 A was supplemented from the spectrograms recorded on a 10.7-m grazing incidence spectrograph of NIST laboratory USA. The sources used to excite the spectra in both the cases were triggered spark. Previously reported levels of 5s25p2, 5s5p3, 5s25p5d and 5s25p6s in Ba VII have been confirmed except the 1P1 level of 5s25p5d. The analysis has been extended considerably to include new configurations 5s25p6d and 5s25p7s in odd parity configuration and doubly excited configurations 5s25p6p, 5s25p4f, 5s25p5f, 5p4, 5s5p25d and 5s5p26s in even parity configuration. The 3F4 level of 5s25p5d configuration has now been established through the identification of transitions from 5s25p6p. In all, one hundred twenty-two levels have been established in this spectrum out of which ninety-two are new. A configuration interaction Hartree–Fock calculation supports the analysis. |
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