The visible spectrum of manganese hydride: Rotational analyses of the 480- and 450-nm systems

Balfour, Walter J.; Lindgren, B.; Launila, O.; O'Connor, Seamus; Cusack, E.J.

doi:10.1016/0022-2852(92)90038-p

Cited by 9 publications

(10 citation statements)

References 12 publications

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“…For these, the exoergicity of the fully ground-state reaction is respectively about +94, -37, and about +33 kJ mol -1 respectively, requiring reagent electronic or translational excitation for any chemiluminescence to be observed. Collision energy-dependent emission from the c 5 Σ + , d 5 Π, and e 5 Σ + states of MnCl* or MnF* has been observed in all three cases, with the b 5 Π state also being found for Mn + SiCl 4 and SF 6 and the A 7 Π state detected for Mn + SF 6 alone. From the measured thresholds, and other considerations, metastable Mn atoms do seem to be the reagent species, but nonetheless, all chemiluminescent channels show significant excess barriers.…”

Section: Introductionmentioning

confidence: 77%

“…By comparison with the previous investigations of Mn + SnCl 4 , SiCl 4 , SF 6 , the most likely excited reagent species might be expected to be the a 6 D J state. Production of all the observed quintet states from z 8 P J atoms is spin-forbidden, and indeed, the only Mn-halide cases so far studied where z 8 P J atoms have been implicated are the spin-allowed A 7 Π channels of Mn + SF 6 , F 2 , and Cl 2 , 11,12 a process clearly absent here.…”

Section: Discussionmentioning

confidence: 96%

“…The investigations so far published comprise Mn + SnCl 4 , SiCl 4 , SF 6 . For these, the exoergicity of the fully ground-state reaction is respectively about +94, -37, and about +33 kJ mol -1 respectively, requiring reagent electronic or translational excitation for any chemiluminescence to be observed.…”

Section: Introductionmentioning

confidence: 99%

“…Some five to six different band systems contribute to the electronic spectroscopy of the manganese monohalides, MnX. − Until recently, only the UV system had been definitively assigned, as AΠ → X 7 Σ + . Now, however, the MnF bands at ∼690 and ∼505 nm have been characterized as c 5 Σ + −a 5 Σ + and d 5 Π−a 5 Σ + , respectively, , with the ∼825 nm system being attributed to b 5 Π−a 5 Σ + , by analogy with MnH .…”

Section: Introductionmentioning

confidence: 99%

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Chemiluminescence in the Reaction of Mn Atoms with CF₄

Herbertson¹,

Levy²

1996

J. Phys. Chem.

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Translational excitation functions have been determined for production of several MnF* statessb 5 Π, c 5 Σ + , d 5 Π, and (most probably) e 5 Σ + sin the reaction of a laser-ablated beam of Mn atoms with gaseous CF 4 . Although all observed channels show high initial thresholds, ∼200-300 kJ mol -1 , reaction appears to be due to excited Mn atoms rather than the ground state, a 6 S. The reagent species appears to be either the first or third metastable level, a 6 D J or a 4 D J . Analysis of the energy dependences, in terms of a multiple line-ofcenters model [Levy, Res. Chem. Kinet. 1993, 1, 163], indicates that at relatively low energies, a common process is responsible for b 5 Π and c 5 Σ + formation, involving a ∼14% forward shift in reaction transition state as collision energy increases. Quite separate processes, without transition state shifts, lead to production of MnF*(d 5 Π) and of MnF*(e 5 Σ + )/"blue" emission at relatively low energies and to enhanced c 5 Σ + production at high energies. It is possible that enhanced production of MnF*(e 5 Σ + ) and perhaps the d 5 Π state from ∼650-700 kJ mol -1 derives from the depletion of MnF*(b 5 Π, c 5 Σ + ). Despite the undoubted negative CF 4 electron affinity, it seems likely that avoided ionic-covalent curve crossings at least play a role in the b 5 Π/ c 5 Σ + production channel.

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Section: Introductionmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Chemiluminescence in the Reaction of Mn Atoms with CF₄

Herbertson¹,

Levy²

1996

J. Phys. Chem.

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“…Most of the MnF and MnCl band systems observed have been well characterised spectroscopically, [24][25][26][27][28][29][30][31][32][33] the main exception being e 5 S + -a 5 S + , which was originally reported as a fragment in absorption by Mesnage, 24 and which was assigned in this laboratory 17,18 by analogy with MnH. 34 For both monohalides the A 7 P-X 7 S + , e 5 S + -a 5 S + and d 5 P-a 5 S + systems fall in the same respective detection regions, i.e. 330-380 nm ('UV'), 417-470 nm ('blue') and 490-510 nm ('green').…”

Section: Introductionmentioning

confidence: 99%

State-to-state chemiluminescence in reactions of Mn atoms with S2Cl2

Khanniche

Levy

2011

Phys. Chem. Chem. Phys.

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A combined experimental and time-dependent density functional theory (TDDFT) investigation of the title reaction is presented. Both 'hot' and 'cold' laser-ablated Mn atom beams have been employed to determine the translational excitation functions for production of MnCl*(c(5)Σ(+), d(5)Π, e(5)Δ, e(5)Σ(+), A(7)Π). Analysis in terms of the multiple line-of-centres approach shows that the 'hot' results are dominated by reactions of the second metastable state of Mn, z(8)P(J), all with very low thresholds; while the first metastable state, a(6)D(J), and the ground state, a(6)S, are the precursors in the 'cold' results, all with significant excess barriers. The post-threshold behaviour of most z(8)P(J) and a(6)D(J) reaction channels implies that the transition states shift forward with increasing collision energy. The TDDFT calculations suggest that, while Mn*(z(8)P(J), a(6)D(J)) insertion into the S-Cl bond is facile, the observed chemiluminescence channels mostly derive from abstraction in a preferred linear Mn-Cl-S configuration, and that the low z(8)P(J) thresholds originate from attractive but excited reagent potentials which either reach a seam of interactions in the product valley or (in the c(5)Σ(+) case) lead to an octet potential very close in energy to the product sextet. The excess barriers in the Mn*(a(6)D(J)) and Mn(a(6)S) reactions appear for the most part to derive from exit channel mixing with lower-lying product potentials. The observed transition state shifts are consistent with the system being forced to ride up the repulsive wall of the entrance valley as collision energy increases, the location of that wall being different for the z(8)P(J) and a(6)D(J) cases.

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