Rydberg-valence interactions of CO, and spectroscopic evidence characterizing the C valence state (original) (raw)
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The Journal of Chemical Physics, 2004
Rotationally cold absorption and two-photon ionization spectra of CO in the 90–100 nm region have been recorded at a resolution of 0.3–1.0 cm−1. The analyses of up to four isotopomers seek to clarify the observations in regions where the Rydberg levels built on the ground state X 2Σ+ of the ion interact with valence states of 1Σ+ and 1Π symmetry. Previous observations of the 3sσ, B 1Σ+ Rydberg state, reviewed by Tchang-Brillet et al. [J. Chem. Phys. 96, 6735 (1992)], have been extended to energies above its avoided crossing with the repulsive part of the D′ 1Σ+ valence state where resonances of varying intensities and widths have been attributed to the fully coupled 3sσ or 4sσ and D′ potentials, and where the B state approaches a second avoided crossing with the C′ 1Σ+ valence state [Cooper and Kirby, J. Chem. Phys. 87, 424 (1987); 90, 4895 (1989); Chem. Phys. Lett. 152, 393 (1988)]. Fragments of a progression of weak and mostly diffuse bands, observed for all four isotopomers, have...
The Journal of Chemical Physics, 2004
Rotationally cold absorption and two-photon ionization spectra of CO in the 90-100 nm region have been recorded at a resolution of 0.3-1.0 cm Ϫ1 . The analyses of up to four isotopomers seek to clarify the observations in regions where the Rydberg levels built on the ground state X 2 ⌺ ϩ of the ion interact with valence states of 1 ⌺ ϩ and 1 ⌸ symmetry. Previous observations of the 3s, B 1 ⌺ ϩ Rydberg state, reviewed by Tchang-Brillet et al. ͓J. Chem. Phys. 96, 6735 ͑1992͔͒, have been extended to energies above its avoided crossing with the repulsive part of the DЈ 1 ⌺ ϩ valence state where resonances of varying intensities and widths have been attributed to the fully coupled 3s or 4s and DЈ potentials, and where the B state approaches a second avoided crossing with the CЈ 1 ⌺ ϩ valence state ͓Cooper and Kirby, J. Chem. Phys. 87, 424 ͑1987͒; 90, 4895 ͑1989͒; Chem. Phys. Lett. 152, 393 ͑1988͔͒. Fragments of a progression of weak and mostly diffuse bands, observed for all four isotopomers, have been assigned to the CЈ←X transition. The least-squares modeling of the 4p and 5p complexes reveals the 3p, E 1 ⌸ Rydberg state to be one of the perturbers, violating the ⌬vϭ0 selection rule for Rydberg-Rydberg interactions on account of its rapid transition with increasing v from Rydberg to valence state. A second 1 ⌸ perturber, very loosely bound and clearly of valence type, contributes to the confusion in the published literature surrounding the 5p, vϭ0 complex.
Vibronic Couplings in the C 1s → n sσ g Rydberg Excited States of CO 2
The Journal of Physical Chemistry, 1996
Fragment ion yields in the C 1s f Rydberg excitation region of CO 2 were measured in the 90°and 0°d irections relative to the electric vector of the linearly polarized light. The C 1s f ns (n) 3, 4), npπ and npσ (n) 3-7), and nd (n) 3, 4) Rydberg transitions are clearly observed and show some vibrational structures. The dipole-forbidden C 1s(σ g) f 3sσ g Rydberg transition is the strongest of all the Rydberg transitions, and the ion yield in the 90°direction is dominant. This indicates that the bending vibration is predominantly coupled with the 3sσ g Rydberg state and the intensity-lending dipole-allowed state is a very strong π* resonance, only 2 eV lower than the 3sσ g state. On the other hand, in the 4sσ g Rydberg state the vibronic coupling through the antisymmetric stretching mode is strongly observed in the 0°direction. This is probably because the 4sσ g state approaches another intensity-lending state with Σ u + symmetry and goes away from the π* resonance. The angle-resolved ion-yield technique is very powerful for elucidating the vibronic coupling mechanism.
Regardless of the theory used for understanding atomic construction, equations that define atomic spectra must include as a derivative the Rydberg equation describing hydrogen and other single-electron ions. The following work product is evidence that defining all elemental spectra is achievable by merely changing some assumptions. The first assumption is that using integers in calculating spectra is incorrect. The second is that spin values for electrons in atoms begin at a ground state level and increase in spin-1 increments due to adding photons of spin-1. The third assumption is that photons are dual spin-1/2 composites. Using spin-1/2 as a basis produces a set of Rydberg-style equations providing spectra for all elements and their many ionic forms. The presented examples, hydrogen through neon, plus phosphorus, a spin-1/2 nucleus, reveal the equation behavior for elements of varying character. Unfortunately, determining which spectral lines dominate in multiple electron atoms is not straightforward without a solid theoretical underpinning. Current theory is lacking or it would be able to provide a similar solution. The term ‘preliminary’ in the title indicates that more than one equation solution exists for multi-electron ions. The equation sets provided represent the most logical and reasonable solutions. Although dominant line prediction is not yet forthcoming, an explanation for photon production using a combination of equation components is proffered. The enclosed information should lead to a full explanation once solutions for all elements are determined and examined in detail and theory further develops.
Predissociation of the Rydberg states of CO: State specific predissociation to the triplet channel
The Journal of Chemical Physics, 1998
Photofragment yield spectra of the 3dπL′ 1Π(v=1) and 4pπL 1Π(v=0) Rydberg states have been observed by monitoring the fragment atoms generated by the predissociation. The Rydberg states of CO were prepared by two-color double resonant excitation through the 3sσB 1Σ+ state, and both C(3P and 1D) and O(3P) atom fragments were observed by two-photon resonant three photon (2+1) ionization. In particular, it has been found that the C(1D) fragmentation takes place in these Rydberg states, which is the first evidence of the predissociation to the triplet channel. Predissociation rates to the triplet channel were estimated, indicating that the rates are comparable to those to the singlet channel.
Chemical Physics Letters, 1999
Angle-resolved ion-yield spectra are reported for the C1s ™ Rydberg excitations of linear acetylene C H in comparison 2 2 with N and CO. The 3s U valence state is observed in the 3ss Rydberg region with no mixing. The 3ps state is found in 2 u g u the same region as the C1ss ™ 3pp state, which shows only totally symmetric vibrations. This is the first to observe that g u the Rydberg state in C H keeps gerade and ungerade symmetries without vibronic coupling through antisymmetric 2 2 stretching vibrations related to core-hole localization. On the other hand, the lowest 1p U valence state induces vibronic g coupling through bending vibrations in the 3s U and 3ss states.
Predissociation of the 4ppLP Rydberg state of carbon monoxide
2002
Time-domain and frequency-domain spectroscopic experiments have been performed on the ð4ppÞLP, v 1⁄4 0 Rydberg state in three isotopomers of carbon monoxide. Accurate values for the excited state lifetimes of the f-parity components have been determined: sðCOÞ 1⁄4 1:08 0:05 ns, sðCOÞ 1⁄4 72 10 ps and sðCOÞ 1⁄4 29 6 ps. The spectral resolution in the frequency-domain experiment goes as far as the limit imposed by the natural lifetime; Qbranch lines, or f-parity components of the heavier isotopes, are resolved for the first time. Highly accurate transition frequencies are determined in a molecular beam experiment using comparison and interpolation with a saturated iodine reference standard. The results reveal a number of perturbations and predissociation mechanisms, displaying a high degree of complexity in the energetic region of the 4p Rydberg states of CO with strong isotopic effects. 2002 Elsevier Science B.V. All rights reserved.
Predissociation of the 4pπL1Π Rydberg state of carbon monoxide
Chemical Physics, 2002
Time-domain and frequency-domain spectroscopic experiments have been performed on the ð4ppÞL 1 P, v ¼ 0 Rydberg state in three isotopomers of carbon monoxide. Accurate values for the excited state lifetimes of the f-parity components have been determined: sð 12 C 16 OÞ ¼ 1:08 AE 0:05 ns, sð 13 C 16 OÞ ¼ 72 AE 10 ps and sð 13 C 18 OÞ ¼ 29 AE 6 ps. The spectral resolution in the frequency-domain experiment goes as far as the limit imposed by the natural lifetime; Qbranch lines, or f-parity components of the heavier isotopes, are resolved for the first time. Highly accurate transition frequencies are determined in a molecular beam experiment using comparison and interpolation with a saturated iodine reference standard. The results reveal a number of perturbations and predissociation mechanisms, displaying a high degree of complexity in the energetic region of the 4p Rydberg states of CO with strong isotopic effects.
High resolution double-resonance spectroscopy on Rydberg states of CO
The Journal of Chemical Physics, 1993
The Rydberg states L 'lI(u=O), L' 'II(u= l), K'Z+(v=O), W 'II(u=O>, and W' 'II(v=2) have been studied in a 2 + 1 double-resonance detection scheme with a resolution of 0.005 cm-'. Accurate molecular constants have been derived for these states. From the observed linewidths of individual rotational transitions, predissociation rates for the Rydberg states have been deduced. For the first time a clear J and e/f dependence for the predissociation of CO has been observed. One of the states causing the observed predissociation could be identified as the D' '2+ state.