High Resolution Laser Spectroscopy of H2at 86–90 nm

Reinhold, E.M.; Hogervorst, W.; Ubachs, Wim

doi:10.1006/jmsp.1996.0236

Cited by 21 publications

(15 citation statements)

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“…resulting in determination of transition frequencies at %0.05 cm À1 accuracy [81][82][83]. An important step in the improvement of the accuracy was the implementation of a so-called pulsed dye-amplifier (PDA) producing the fundamental laser radiation, that is then frequency sextupled in two consecutive nonlinear processes: frequency-doubling in crystals and frequency-tripling in a gas jet.…”

Section: H 2 Spectroscopy In the Laboratorymentioning

confidence: 99%

On a possible variation of the proton-to-electron mass ratio: H2 spectra in the line of sight of high-redshift quasars and in the laboratory

Ubachs

Buning

Eikema

et al. 2007

Journal of Molecular Spectroscopy

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124

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Recently the finding of an indication for a decrease of the proton-to-electron mass ratio l = m p /m e by 0.002% in the past 12 billion years was reported in the form of a Letter [E. Reinhold, R. Buning, U. Hollenstein, P. Petitjean, A. Ivanchik, W. Ubachs, Phys. Rev. Lett. 96 (2006) 151101]. Here we will further detail the methods that led to that result and put it in perspective. Laser spectroscopy on molecular hydrogen, using a narrow-band and tunable extreme ultraviolet laser system at the Laser Centre Vrije Universiteit Amsterdam, results in transition wavelengths of spectral lines in theWerner band systems at an accuracy of (4-11) · 10 À8, depending on the wavelength region. This corresponds to an absolute accuracy of 0.000004-0.000010 nm. A database of 233 accurately calibrated H 2 lines is presented here for future reference and comparison with astronomical observations. Recent observations of the same spectroscopic features in cold hydrogen clouds at redshifts z = 2.5947325 and z = 3.0248970 in the line of sight of two quasar light sources (Q 0405À443 and Q 0347À383) resulted in 76 reliably determined transition wavelengths of H 2 lines at accuracies in the range 2 · 10 À7 to 1 · 10 À6 . Those observations were performed with the Ultraviolet and Visible Echelle Spectrograph at the Very Large Telescope of the European Southern Observatory at Paranal, Chile. A third ingredient in the analysis is the calculation of an improved set of sensitivity coefficients K i , a parameter associated with each spectral line, representing the dependence of the transition wavelength on a possible variation of the proton-to-electron mass ratio l. The new model for calculation of the K i sensitivity coefficients is based on a Dunham representation of ground state and excited state level energies, derived from the most accurate data available in literature for the X 1 R þ g ground electronic state and the presently determined level energies in the B 1 R þ u and C 1 P u states. Moreover, the model includes adiabatic corrections to electronic energies as well as local perturbation effects between B and C levels. The full analysis and a tabulation of the resulting K i coefficients is given in this paper. A statistical analysis of the data yields an indication for a variation of the proton-to-electron mass ratio of Dl/l = (2.45 ± 0.59) · 10 À5 for a weighted fit and Dl/l = (1.99 ± 0.58) · 10 À5 for an unweighted fit. This result, indicating the decrease of l, has a statistical significance of 3.5r. Mass-variations as discussed relate to inertial or kinematic masses, rather than gravitational masses. Separate treatment of the data gives a similar positive result for each of the quasars Q 0405À443 and Q 0347À383. The statistical analysis is further documented and possible systematic shifts underlying the data, with the possibility of mimicking a non-zero Dl/l value, are discussed. The observed decrease in l corresponds to a rate of change of d lnl/dt = À2 · 10 À15 per year, if a linear variation with time is assumed. Expe...

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Section: H 2 Spectroscopy In the Laboratorymentioning

confidence: 99%

On a possible variation of the proton-to-electron mass ratio: H2 spectra in the line of sight of high-redshift quasars and in the laboratory

Ubachs

Buning

Eikema

et al. 2007

Journal of Molecular Spectroscopy

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124

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“…1 Since that time the older data have been completed by more recent experiments of ever increasing precision, culminating in recent years in high resolution laser measurements which have an absolute accuracy of a few GHz. [2][3][4] At the same time theoretical ab initio electronic potential energy curves for the lowest excited states as well as nuclear coupling functions connecting these of ever increasing accuracy have been published, primarily by the group of Wolniewicz. 5 Using these ab initio data, it is now possible to make predictions of rovibronic level energies fully from first principles, and compare these with experimental data.…”

Section: Introductionmentioning

confidence: 99%

Theory of vibronic interactions in D2 and H2: A comparison between multichannel-quantum-defect and coupled-equation approaches

Glass‐Maujean

Jungen

Roudjane

et al. 2011

The Journal of Chemical Physics

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New experimental energy levels for the 2pπC(1)Π(u)(-) state of D(2) are reported extending up to the dissociation limit and including rotational quantum numbers up to N = 10. These data are extracted from recent high resolution optical emission spectra, and they are used for a detailed comparison of two theoretical approaches, both of which are fully ab initio and are based on the same state-of-the-art clamped-nuclei potential energy curves. These are the coupled differential equations (CE) and the multichannel quantum defect theory (MQDT) approaches, each of which accounts for adiabatic corrections and non-adiabatic couplings. Both theoretical approaches reproduce the experimental levels to within a fraction of a wavenumber unit (cm(-1)) for the lower vibrational quantum numbers, with the MQDT surpassing the CE method. As the dissociation limit is approached, the residuals observed-calculated increase up to several cm(-1) and the MQDT method is up to a factor of two less accurate than the CE method. The same analysis is carried out with existing data for the H(2) isotopomer and yields similar results. An analogous comparison is also made for the 3pπD(1)Π(u)(-) and 4pπD('1)Π(u)(-) states for both isotopomers, where the MQDT is found to be superior to the CE approach.

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“…Baig and Connerade [19] performed an absorption study on H 2 using synchrotron radiation, while Jungen et al [20] determined level energies for the B, v = 0 and 1 states by cascaded infrared transitions, using Fourier-transform infrared (FTIR) spectroscopy. The Amsterdam group performed extensive wavelength calibration studies on the Lyman bands of H 2 [21,22] and HD [23], using a laser-based VUV source allowing for an absolute uncertainty of the transition frequencies of better than 0.1 cm −1 . Since the resolution of the Amsterdam VUV laser system was improved by a factor of 20 [24], investigations of the Lyman bands for v = 2-18 could be performed, yielding absolute accuracies of 10 −7 or better [25].…”

Section: Introductionmentioning

confidence: 99%

High-resolution VUV-laser spectroscopic study of the B¹Σ⁺_(u)(v′ = 0–2)← X¹Σ⁺_(g)(v″ = 0) Lyman bands in H₂and HD

Hollenstein¹,

Reinhold²,

Lange³

et al. 2006

J. Phys. B: At. Mol. Opt. Phys.

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High Resolution Laser Spectroscopy of H2at 86–90 nm

Abstract: A narrowband and tunable extreme ultraviolet laser source was employed to study the absorption spectrum of molecular hydrogen in the range 86-90 nm. Frequencies of transitions to the

Cited by 21 publications

References 5 publications

On a possible variation of the proton-to-electron mass ratio: H2 spectra in the line of sight of high-redshift quasars and in the laboratory

On a possible variation of the proton-to-electron mass ratio: H2 spectra in the line of sight of high-redshift quasars and in the laboratory

Theory of vibronic interactions in D2 and H2: A comparison between multichannel-quantum-defect and coupled-equation approaches

High-resolution VUV-laser spectroscopic study of the B¹Σ⁺_(u)(v′ = 0–2)← X¹Σ⁺_(g)(v″ = 0) Lyman bands in H₂and HD

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High Resolution Laser Spectroscopy of H2at 86–90 nm

Abstract: A narrowband and tunable extreme ultraviolet laser source was employed to study the absorption spectrum of molecular hydrogen in the range 86-90 nm. Frequencies of transitions to the

Cited by 21 publications

References 5 publications

On a possible variation of the proton-to-electron mass ratio: H2 spectra in the line of sight of high-redshift quasars and in the laboratory

On a possible variation of the proton-to-electron mass ratio: H2 spectra in the line of sight of high-redshift quasars and in the laboratory

Theory of vibronic interactions in D2 and H2: A comparison between multichannel-quantum-defect and coupled-equation approaches

High-resolution VUV-laser spectroscopic study of the B1Σ+(u)(v′ = 0–2)← X1Σ+(g)(v″ = 0) Lyman bands in H2and HD

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High-resolution VUV-laser spectroscopic study of the B¹Σ⁺_(u)(v′ = 0–2)← X¹Σ⁺_(g)(v″ = 0) Lyman bands in H₂and HD