Laser spectroscopy of NiBr: Ground and low-lying electronic states

Abstract

Four electronic states of NiBr have been studied using the technique of laser vaporization/reaction with supersonic cooling and laser induced fluorescence ͑LIF͒ spectroscopy. NiBr molecules were produced by reacting laser ablated nickel atoms and ethyl bromide (C 2 H 5 Br). High resolution LIF spectrum between 724 and 810 nm was recorded, which consists of the ͑2,0͒, ͑1,0͒, and ͑0,0͒ bands of the ͓13.2͔ 2 ⌸ 3/2-X 2 ⌸ 3/2 system and the ͓13.2͔ 2 ⌸ 3/2-A 2 ⌬ 5/2 system, and also the (v,0) with vϭ0-4 bands of the ͓12.6͔ 2 ⌺ ϩ-X 2 ⌸ 3/2 system. Spectra of four isotopic molecules: 58 Ni 79 Br, 58 Ni 81 Br, 60 Ni 79 Br, and 60 Ni 81 Br were observed and analyzed. Least squares fit of rotationally resolved transition lines yielded accurate molecular constants for the X 2 ⌸ 3/2 , A 2 ⌬ 5/2 , ͓12.6͔ 2 ⌺ ϩ , and ͓13.2͔ 2 ⌸ 3/2 electronic states of NiBr. The bond length, r 0 , measured for the X 2 ⌸ 3/2 and A 2 ⌬ 5/2 states is 2.196 28 and 2.164 45 Å, respectively. A molecular orbital diagram has been constructed to explain the four observed electronic states. This work represents the first high-resolution spectroscopic study of NiBr.

Fourier transform spectroscopy of NiCl: identification of a [9.1] state

“…2. For comparison, the known states of the nickel halides [1][2][3][4][5][6][13][14][15] are presented in Fig. 3.…”

Spectroscopy of NiCl: Identification of the X2Π1/2 state

“…The X 2 P 1/2 state was previously recorded at low resolution, observed in dispersed fluorescence experiments [1,2]. The electronic structure of the low-lying states of NiCl is found to be similar to that of NiF [11][12][13], NiBr [14], and NiI [15,16].…”

Spectroscopy of nickel chloride: Identification of the [15.0] 2Π3/2 and [15.0] 2Δ5/2 states

“…Descriptions of the spectrometer and the laser ablation system are given in detail elsewhere [20,21]. Only a brief description of the experimental conditions will be given here.…”