Perturbation-facilitated optical-optical double resonance spectroscopy of the h0u−(3P1) and H1u(3P1) ion-pair states of I2

Abstract

Perturbation-facilitated optical-optical double resonance spectroscopy has been applied to study the h0u−(3P1) and H1u(3P1) ion-pair states of I2 correlating with I−(1S)+I+(3P1). The intermediate states used were the g/u parity mixed states found in the B 3∏(0u+)−X 1∑g+ absorption spectrum near the dissociation limit. We identified several B 3∏(0u+)∼3∏(0g−) coupled states by hyperfine interactions for the first time. These states had the 0u+ and 0g− double-faced character and facilitated to combine the X 1∑g+ ground state with the h0u−(3P1) state in the (1+1) photon excitation scheme following the optical selection rules for one-photon transition. We also accessed the H1u(3P1) state through the B 3∏(0u+)∼c1g mixed state, and elucidated the heterogeneous coupling between the h0u−(3P1) and H1u(3P1) states. Our analyses covered the region of about 48 200 to 50 300 cm−1, and gave the molecular parameters of the h0u−(3P1) state valid for v=0–17 and those of the H1u(3P1) state for v=0–20. The Π3(0g−) state used as an intermediate state was analyzed through the dispersed h0u−(3P1)−3∏(0g−) emission in conjunction with the Franck–Condon factor calculations, and the principle spectroscopic constants of the Π3(0g−) state were reported.

Analysis of the g−(3P1)–B ′3 Π(0u−) system of I2 by perturbation-facilitated optical–optical double resonance

“…D, the T e value is corrected by using the updating data of the 0 g Ϫ ( 3 P 1 ) -B Ј 3 ⌸(0 u Ϫ ) emission reported by Tellinghuisen. 12 In obtaining the vibrational parameters, we used 121 vibronic transitions originating from the 0 g Ϫ ( 3 P 1 ) state in the range vϭ5, 6,8,9,11,13, and 14. The standard deviation of the fitting was 0.36 cm Ϫ1 .…”

“…13 Briefly, we have used two tunable lasers pumped by a Nd 3ϩ :YAG laser. A pump laser excited the visible B 3 ⌸(0 u ϩ ) -X 1 ⌺ g ϩ absorption line of I 2 at a fixed frequency (h 1 ).…”

Observation and analysis of the 2g(1D) ion-pair state of I2: The g/u mixing between the 1u(1D) and 2g(1D) states

“…It gives rise to a g-u symmetry breaking in the electronic states sharing the same dissociation limit as observed in H 2 ϩ , 27 I 2 , 28 and Cs 2 . 14,15,21 It implies that the g/u mixing might be common in the ion-pairs states of I 2 . The present study provides a distinct example of the g/u mixing where only two electronic states are involved in a simple spectral region.…”

“…Therefore, the studies were principally limited to the ⍀ϭ0 ϩ states using the B 3 ⌸(0 u ϩ ) intermediate state and our systematic approach to identify all of the ion-pair states has failed. [15][16][17] The purpose of this paper is to report the analysis of the 2 g ( 1 D) ion-pair state. 12,13 Recently, we have started a new program of studies on the ion-pair states by perturbation-facilitated optical-optical double resonance.…”

Observation of three weakly bound valence states of I2

“…[2][3][4][5] Further eight states, BЈ0 u − ͑aa͒, a1 g ͑aa͒, C1 u ͑aa͒ ͑sometimes labeled as BЉ͒, aЈ0 g + ͑aa͒, 0 g + ͑ab͒, c1 g ͑ab͒, 0 g − ͑ab͒, and bЈ2 u ͑ab͒, have been shown experimentally to be weakly bound. [6][7][8][9][10][11][12] None of the remaining eleven states have been characterized experimentally, although emission from various ion-pair states to the 2 g ͑aa͒, 0 u − ͑ab͒, 1 g ͑ab͒, 1 u ͑ab͒, and 2 g ͑ab͒ states has been observed. 6,13 We can only find two reports of observations of any of the three states that correlate with the ͑bb͒ limit ͑1 g ,0 g + ,0 u − ͒ in gas-phase studies.…”