Rydberg and pulsed field ionization-zero electron kinetic energy spectra of YO (original) (raw)
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High resolution molecular beam study of the origin band of the B˜ 2Σ+–X˜ 2Σ+ system of yttrium imide
1999
The ͑0,0,0͒-͑0,0,0͒ band of the B 2 ⌺ ϩ -X 2 ⌺ ϩ system of three isotopomers of yttrium imide (Y 14 NH, Y 15 NH, and Y 14 ND) has been studied by laser-induced fluorescence in a molecular beam apparatus. Rotational, fine, and nuclear magnetic hyperfine structures have been resolved and analyzed. The B 2 ⌺ ϩ (0,0,0) state of Y 14 NH, Y 14 ND, and Y 15 NH is severely perturbed below J ϭ30.5 by eight, three, and two vibronic states, respectively. Although, the nature of these perturbing states can only be speculated upon, their symmetries are either 2 ⌺ or 2 ⌸, and this has made it possible to deperturb the B 2 ⌺ ϩ state successfully. The spectra can be reproduced within 140 MHz ͑0.0047 cm Ϫ1 ͒. The analyses confirm that the molecule is linear in both states with the nuclear arrangement Y-N-H. The bond lengths in the ground X 2 ⌺ ϩ state and the B 2 ⌺ ϩ state have been derived to be r Y-N ϭ1.877 57(13) Å, r N-H ϭ1.0067(10) Å, and r Y-N ϭ1.8839(43) Å, r N-H ϭ1.242(30) Å, respectively. The results are compared with the values of ab initio calculations on YNH and YN, and the experimental data on YN and YO. The atomic character of the unpaired electron in the ground state is 58% Y ϩ 5s and 42% Y ϩ 5 p. The electron configurations for the ground X 2 ⌺ ϩ state and the B 2 ⌺ ϩ state are discussed and compared with ab initio calculations whenever possible.
Inner shell and double excitation spectrum of ytterbium involving the 4f and 6s subshells
Journal of Physics B-atomic Molecular and Optical Physics, 1992
The absorption spectrum of ytterbium in the wavelength range 1200-2000 A has been recorded in the first order of a 3 m spectrograph equipped wilh a 6000 line mm-' holographic grating, using synchrotron radiation as the background source of continuum. More than 200 new levels of Yb I are reponed which are interpreted as the inner shell transitions, 4P46s2 + 4f13(2F,/,,,/,)nd, ng and the doubly excited transitions, 4f"6s2 -4f145d(2D,/,,,/2)np, nf and 4f"6s2 -4f'46p(zP,/2,3/2)ns, nd All the observed levels lie above the first ionization threshold and can be ordered into Rydberg Series converging onlo six limits. The interchannel interactions between the overlapped series have been parametrized using multichannel quantum defect theoty. PI n! 1985, Kaenders e! a! 1990). The. annearanre. rr ifite.gx~mbin~tiofi !ices C i n n D I r -'6''"'Y the breakdown of the L S coupling selection rules. From the observed long Rydberg series, which are amenable to an MQDT analysis, an accurate first ionization limit of ytterbium is derived as 50 443.08 + 0.05 cm-' .
Spectroscopy of YO from first principles
Physical Chemistry Chemical Physics
We report an ab initio study on the spectroscopy of the open-shell diatomic molecule yttrium oxide, YO. The study considers the six lowest doublet states, X2Σ+, A'2Δ, A2Π, B2Σ+, C2Π,...
The Journal of Chemical Physics, 1999
The ͑0,0,0͒-͑0,0,0͒ band of the B 2 ⌺ ϩ -X 2 ⌺ ϩ system of three isotopomers of yttrium imide (Y 14 NH, Y 15 NH, and Y 14 ND) has been studied by laser-induced fluorescence in a molecular beam apparatus. Rotational, fine, and nuclear magnetic hyperfine structures have been resolved and analyzed. The B 2 ⌺ ϩ (0,0,0) state of Y 14 NH, Y 14 ND, and Y 15 NH is severely perturbed below J ϭ30.5 by eight, three, and two vibronic states, respectively. Although, the nature of these perturbing states can only be speculated upon, their symmetries are either 2 ⌺ or 2 ⌸, and this has made it possible to deperturb the B 2 ⌺ ϩ state successfully. The spectra can be reproduced within 140 MHz ͑0.0047 cm Ϫ1 ͒. The analyses confirm that the molecule is linear in both states with the nuclear arrangement Y-N-H. The bond lengths in the ground X 2 ⌺ ϩ state and the B 2 ⌺ ϩ state have been derived to be r Y-N ϭ1.877 57(13) Å, r N-H ϭ1.0067(10) Å, and r Y-N ϭ1.8839(43) Å, r N-H ϭ1.242(30) Å, respectively. The results are compared with the values of ab initio calculations on YNH and YN, and the experimental data on YN and YO. The atomic character of the unpaired electron in the ground state is 58% Y ϩ 5s and 42% Y ϩ 5 p. The electron configurations for the ground X 2 ⌺ ϩ state and the B 2 ⌺ ϩ state are discussed and compared with ab initio calculations whenever possible.
Three-step laser excitation of the ?, ? J = 1, 2, 3 autoionizing Rydberg levels of lead
Journal of Physics B-atomic Molecular and Optical Physics, 1997
We report here first measurements of the odd-parity 0953-4075/30/5/013/img12 J =1, 2 and 0953-4075/30/5/013/img13 J = 0, 1, 2, 3 autoionizing Rydberg levels of lead using a three-step laser excitation scheme in conjunction with an atomic beam apparatus. Four initial levels 0953-4075/30/5/013/img14 J = 1, 2 were chosen for the excitation of the final levels. The assignments have been made using the 0953-4075/30/5/013/img15-coupling scheme for the observed levels. The Rydberg series 0953-4075/30/5/013/img16, 0953-4075/30/5/013/img17, 0953-4075/30/5/013/img18 and 0953-4075/30/5/013/img19 as well as 0953-4075/30/5/013/img20 are reported. All the observed series exhibit constant quantum defects with respect to the ionization potential value 0953-4075/30/5/013/img21. The full widths at half the maximum 0953-4075/30/5/013/img22 of the observed levels are also reported.
Zeitschrift f�r Physik D Atoms, Molecules and Clusters, 1987
The energies of 190 Rydberg and autoionization 4 f 13 6snp-states of the Tm atom (ground electron configuration 4 f ~3 6s 2, nuclear charge Z=69) have been measured by the laser multistep excitation with subsequent electric field ionization method. The investigation range of these states has been extended towards states with higher and lower values of the principal quantum number. As a result the energies of 160 states have been obtained for the first time. The experiment has been carried out on an automated laser photoionization spectrometer. The measurement accuracy has been _ 0.5 cm-~
Influence of the helium autoionization structures on the single/double ionization signal
The European Physical Journal D, 2002
Calculations of intense field (around 10 16 W/cm 2 ) single-and double-ionization processes in helium at XUV wavelengths are presented. The laser wavelength is chosen near the |2s2p 1 P autoionization structure and the dynamics are explored. Single and double ionization yields, as well as the photoelectron energy spectrum for photon energies around the autoionization structure are calculated. In the case of a pulse of few femtoseconds duration, no significant enhancement of the double ionization yield has been found in tuning the photon frequency around the peak of the resonance. It is also shown that in the case of a long pulse (and hence narrow compared with the relevant autoionization width), the branching ratio of double to single ionization yield can be relatively enhanced by tuning to the absorption minimum of the resonance.
The Journal of Chemical Physics, 2010
Relative partial photoionization cross sections and angular distribution parameters  have been measured for the first and fourth ͑5p͒ −1 photoelectron ͑PE͒ bands of atomic iodine by performing angle-resolved constant-ionic-state ͑CIS͒ measurements on these PE bands between the 1 D 2 and 1 S 0 ͑5p͒ −1 ionic thresholds in the photon energy region of 12.9-14.1 eV. Rydberg series arising from the 5p → ns and 5p → nd excitations are observed in both the first PE band, I + ͑ 3 P 2 ͒ ← I͑ 2 P 3/2 ͒, and the fourth PE band, I + ͑ 1 D 2 ͒ ← I͑ 2 P 3/2 ͒, CIS spectra. For each Rydberg state, the resonance energy, quantum defect, linewidth, line shape, and photoelectron angular distribution parameter  have been determined. For the -plots for each PE band, only resonances corresponding to 5p → nd excitations are observed; no resonances were seen at photon energies corresponding to the 5p → ns resonances in the CIS spectra. The -plots are interpreted in terms of the parity unfavored channel with j t =4 being the major contributor at the 5p → nd resonance positions, where j t is the quantum number for angular momentum transferred between the molecule, and the ion and photoelectron. Comparison of the results obtained with those published for bromine shows reasonably good agreement for the CIS spectra but poor agreement for the -plots. It appears that parity unfavored channels are playing a greater role in the valence ͑np͒ −1 ionization of atomic iodine than in the corresponding ionization of atomic bromine.
Extended Analysis of the Spectrum of Triply-ionized Ytterbium (Yb IV) and Transition Probabilities
Physica Scripta, 2001
The spectrum of Yb IV has been reinvestigated and its analysis has been extended. The present work is supported by the comparison of line intensities with transition probabilities derived from the Cowan (1981) codes. Starting from the ¢rst analysis by Sugar, Kaufman and Spector (1978), the number of established levels has been increased from 111 to 193, including high excitation levels of the new 4f 12 7s+4f 12 6d even con¢gurations. Of the 1023 classi-¢ed lines about one half are new. Computed transition probabilities are given for selected lines.
Three-step excitation of the ?, nd, ng autoionizing Rydberg levels via the 6p6f ? level of lead
Journal of Physics B-atomic Molecular and Optical Physics, 1997
New spectra of lead consisting of the autoionizing Rydberg energy region excited via the 0953-4075/30/19/010/img12 level is presented. Fifty levels along with their FWHM widths are reported. Eleven levels of the 0953-4075/30/19/010/img13 configuration have been reported for the first time. Besides two unassigned levels with effective quantum number 8.446 and 10.86, five new levels of the 0953-4075/30/19/010/img14 configuration have been observed. An unexplained phenomenon is observed where the 0953-4075/30/19/010/img15 levels for n > 14 do not show up via the 0953-4075/30/19/010/img12 route in contrast to the fact they are observed as strong resonances when excited via other similar routes, namely, 0953-4075/30/19/010/img17 and 0953-4075/30/19/010/img18 levels.