Emission Spectroscopy and Ab Initio Calculations on IrN

✍ Scribed by R.S. Ram; J. Liévin; P.F. Bernath

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 323 KB
• Volume: 197
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1999.7911

✦ Synopsis

The emission spectrum of IrN was recorded in the near infrared using a Fourier transform spectrometer. The IrN molecules were excited in an Ir hollow cathode lamp operated with a mixture of Ne and a trace of N 2 . Numerous IrN bands observed in the 7500 -9200 cm Ϫ1 region were assigned to a new a 3 ⌸-X 1 ⌺ ϩ electronic transition with the 0 -0 bands of the a 3 ⌸ 0 -X 1 ⌺ ϩ and a 3 ⌸ 1 -X 1 ⌺ ϩ subbands near 9175 and 8841 cm Ϫ1 , respectively. A rotational analysis of several bands of the 0 -0 and 0 -1 sequences was obtained and molecular constants were extracted. The effective Hund's case (a) constants for the new a 3 ⌸ state are: T 00 ϭ 8840.31747(88) cm Ϫ1 , A 0 ϭ Ϫ340.53329(93) cm Ϫ1 , ⌬G(1/2) ϭ 984.3629(23) cm Ϫ1 , B e ϭ 0.4699116(27) cm Ϫ1 , ␣ e ϭ 0.0030058(50) cm Ϫ1 , and r e ϭ 1.6576432(47) Å. The spectroscopic properties of the ground state and several low-lying electronic states of IrN were also predicted by ab initio calculations. These calculations are consistent with our assignment of the a 3 ⌸-X 1 ⌺ ϩ transition and also support our previous assignments of the AЈ 1 ⌸ and A 1 ⌸ electronic states [R. S. Ram and P. F. Bernath, J. Mol. Spectrosc. 193, 363 (1999)]. The excited a 3 ⌸ state of IrN has an 1 2 2 2 1 4 3 1 1␦ 4 2 1 electron configuration and the configurations of the other low-lying electronic states are also discussed.