New rovibrational analysis of A–X absorption spectrum of

Wu, Ling; Yang, Xiyun; Guo, Yingchun; Zheng, Lijuan; Liu, Yuyan; Chen, Yangqin

doi:10.1016/j.jms.2004.10.009

Cited by 12 publications

(16 citation statements)

References 21 publications

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“…The excited state B values are larger than any of those determined in the early literature and almost identical to those obtained recently from analyses of the 2 1/2 bands at 16 913 and 17 282 cm −1 , tentatively assigned as 2−7 and 3−7. 26 We are led to the definite conclusion that all the bands in our cold spectra originate in the ground state v = 0 X 2 3/2g level. In addition to LIF spectra, we also obtained wavelength resolved emission spectra for many upper state levels.…”

Section: A Description Of the Spectramentioning

confidence: 75%

A new, definitive analysis of a very old spectrum: The highly perturbed A2Πu–X 2Πg band system of the chlorine cation (${\rm Cl}_2^ +$ Cl 2+)

Gharaibeh

Clouthier

Καλέμος

et al. 2012

The Journal of Chemical Physics

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The laser-induced fluorescence spectrum of jet-cooled chlorine cation has been recorded in the 500-312 nm region with high sensitivity and rigorous vibrational and spin-orbit cooling. More than 80 bands of the highly vibrationally perturbed A (2)Π(u)-X (2)Π(g) electronic transition have been detected and shown to originate from the Ω = 3/2 spin-orbit component of v = 0 of the ground state. The spectrum extends some 3700 cm(-1) to the red of any previously published report and the 0-0 band has been identified for the first time. The bands have regular rotational structure but exhibit irregular vibrational intervals and isotope splittings. Our ab initio studies show that the perturbations are due to a ΔΩ = 0 spin-orbit interaction between the A(2)Π(3/2u) and B(2)Δ(3/2u) states which have an avoided crossing at ~2.5 Å, which corresponds to v ≈ 4 of the A state. The nonadiabatic coupled equations have been solved for this two-state interaction after constructing the diabatic potentials including only the diagonal (ΔΛ = 0) spin-orbit coupling, yielding low-lying vibrational energy levels, isotope splittings, and rotational constants in good agreement with experiment. The calculations show that many of the observed bands are actually transitions to predominantly B state vibrational levels, which borrow oscillator strength from the A-X transition through spin-orbit mixing. Starting from the coupled equations solutions, we have fitted the experimental data using an effective Hamiltonian matrix that includes the vibrational energy levels of the A and B states and a single electronic spin-orbit coupling term H(SO)(AB) which has a value of 240 cm(-1). Transitions up to v' = 32 in both states have been satisfactorily fitted for all three chlorine isotopologues, providing a quantitative description of the perturbations. Transitions to higher levels are complicated by interactions with other electronic states.

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Section: A Description Of the Spectramentioning

confidence: 75%

A new, definitive analysis of a very old spectrum: The highly perturbed A2Πu–X 2Πg band system of the chlorine cation (${\rm Cl}_2^ +$ Cl 2+)

Gharaibeh

Clouthier

Καλέμος

et al. 2012

The Journal of Chemical Physics

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“…The molecular constants of the main isotopomer 35 Cl 2 obtained by the fit are listed in Table IV and can be scaled using the appropriate ratios of the reduced masses μ i to yield the corresponding values of the minor isotopomers using the relations 24 In the derivation of these parameters, data from emission spectra for v + = 7 15 and v + = 8 16 was included in the fit.…”

Section: Vibrational Structure Of the Spectramentioning

confidence: 99%

“…Experimental information on the rovibrational and spin-orbit energy level structure of several of these low-lying states has been obtained by photoelectron spectroscopy [4][5][6][7][8][9] and by optical spectroscopy. 2,3,[10][11][12][13][14][15][16] At low resolution, the He I photoelectron spectrum reveals a very simple structure with three main bands centered at ≈11.8, 14.3, and 16 eV, which correspond to three S = 1/2 cationic states that are formed from the (σ g ) 2 (π u ) 4 (π * g ) 4 X 1 + g ground state of Cl 2 by (π * g ) −1 , (π u ) −1 , and (σ g ) −1 single-photon ionization. 5 The spin-orbit and vibrational structure of the bands is observable at higher resolution and the similarity of the vibrational and spin-orbit intervals in the X + and A + states leads to a clustering of the photoelectron bands.…”

Section: Introductionmentioning

confidence: 99%

The X+ 2Πg, A+ 2Πu, B+ 2Δu, and $\mathrm{a}^+\ ^4\Sigma _{\mathrm{u}}^-$a+Σu−4 electronic states of ${\rm Cl}_2^+$ Cl 2+ studied by high-resolution photoelectron spectroscopy

Merkt

2013

The Journal of Chemical Physics

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Photoelectron spectroscopic study of the E ⊗ e Jahn-Teller effect in the presence of a tunable spin-orbit Partially rotationally resolved pulsed-field-ionization zero-kinetic-energy photoelectron spectra of the three isotopomers ( 35 Cl 2 , 35 Cl 37 Cl, and 37 Cl 2 ) of Cl 2 have been recorded in the wavenumber ranges 92 500-96 500 cm −1 , corresponding to transitions to the low vibrational levels of the X + 2 g ( = 3/2, 1/2) ground state of Cl + 2 , and 106 750-115 500 cm −1 , where the a + 4 − u ← X 1 + g , A + 2 u ← X 1 + g , and B + 2 u ← X 1 + g band systems overlap with transitions to high vibrational levels (v + > 25) of the X + state. The observation of Franck-Condon-forbidden transitions to vibrational levels of the X + state of the cation with v + ≥ 25 is rationalized by a mechanism involving vertical excitation of predissociative Rydberg states of mixed singlet-triplet character with an A + ion core which are coupled to Rydberg states converging to high-v + levels of the X + state. The same mechanism is proposed to also be responsible for the observation of Cl + − Cl − ion pairs and quartet states in the photoionization of Cl 2 . The potential energy function of the X + state of Cl + 2 was determined in a direct fit to the experimental data. Transitions to vibrational levels of the A + 2 u, 3/2 and B + 2 u, 3/2 states of Cl + 2 could be identified using the results of a recent analysis of the strong perturbation between the A + 2 u, 3/2 and B + 2 u, 3/2 states of Cl + 2 observed in the A + − X + band system [Gharaibeh et al., J. Chem. Phys. 137, 194317 (2012)], and transitions to several vibrational levels of the upper spin-orbit component ( 2 u, 1/2 ) of the A + state were detected in the photoelectron spectrum of Cl + 2 . The a + 4 − u ← X 1 + g photoelectron band system, which is nominally forbidden by single-photon ionization from the ground state was also observed for the first time and its vibrational and spin-orbit structures were analyzed. The 4 − u state is split into two spin-orbit components with = 1/2 and = 3/2, separated by 37.5 cm −1 . The vibrational energy level structure of both components is regular, which indicates that the splitting results from the interaction with one or more distant ungerade = 1/2 or = 3/2 electronic states. © 2013 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.

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“…They presented a study of N 2 + in their initial paper on this technique 15 and a further study of it in 2001 . In addition Cl 2 + , C 2 - , and CO + have all been measured in the range of 16700−17400 wavenumbers. ,− Near-infrared spectra of 16 O 2 + between 12100 and 14100 cm -1 have been measured. , Subbands of both H 2 O + and D 2 O + have also been measured in both the near-infrared and the visible regions, and finally, the near-infrared spectrum of CS + has been obtained. − …”

Section: 4 Oh-mr-vmsmentioning

confidence: 99%

“…As discussed above, at these very low frequencies, the Doppler shift may not be sufficient to compensate for the pressure-broadened width, which has minimal dependence upon frequency. To circumvent this problem, the Ziurys' group employed very low total pressures within the velocity modulation cell (40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50). Instead of having the usual first-derivative transition profile, the blue-shifted portion of the peak (positive) was bigger than the red-shifted (negative) half by approximately a factor of 4.…”

Section: Millimeter Wave Velocity Modulationmentioning

confidence: 99%