kroll_1990#
S. Kröll and W. K. Bischel, “Two-photon absorption and photoionization cross-section measurements in the 5p5 6p configuration of xenon”, Phys. Rev. A 41, 1340 (1990)
Source record · Catalogue · Review register
Source kind: measurement
Recorded technique: Two-photon cross sections (Sec. II A): two-photon-excited fluorescence of xenon at 10-20 Pa (‘Nonradiative decay (quenching) is not more than 1%’), the 5p5 6p -> 5p5 6s infrared fluorescence (828, 823 and 905 nm, with branching ratios 0.998, 0.70 and 0.36 from refs. 18, 19) on a photomultiplier, the detection efficiency calibrated by spontaneous Raman scattering in H2 at the same wavelengths (ref. 17), single-shot signal against pulse energy (slope 1.01 against E^2, Fig. 1), with measured spatial and temporal beam profiles (Eqs. 1, 2, following Bamford, Jusinski and Bischel, ref. 16). Light: a Nd:YAG-pumped dye laser (R6G, about 557-573 nm), frequency-doubled and Raman-shifted in H2 (the first anti-Stokes line), the vertically polarised part selected by a Pellin-Broca prism; 50-100 uJ through a 1 mm aperture. The laser was scanned over each line (Gaussian, 30 GHz FWHM two-photon width, a laser width of about 20 GHz) and the line-centre value integrated over the line (Eq. 4). Excited-state photoionisation (Sec. II B): fluorescence depletion spectroscopy, the ratio of the 2p5 or 2p6 fluorescence after and before an excimer-laser pulse (193 or 248 nm) against its fluence, I(F) = I(0) exp(-sigma_ion F) (Eq. 5), single shots, the fluence from the energy through a 200 um pinhole; corrected by about 10 % for the ionising beam’s non-uniform fluence (r1/r0 <= 0.5, Sec. III A).
Materials in structured entries: Xe
Dataset quantities: excited_state_photoionization_cross_section, two_photon_excitation_cross_section
Contents: 4 datasets; 0 formulas.
Curation notes#
Phys. Rev. A 41(3), 1340-1349 (1 February 1990) = PDF pages 3-12 of Lund University’s repository copy (a cover and a licence page first; journal page = PDF page + 1337); a scan with a text layer. Identity checked against the first page of the article (journal, volume, pages, authors). Every number taken was checked against the table images and the rendered pages (Table I p. 1346, Table II p. 1347).
LEVELS (Paschen notation, as the paper uses; jl notation from p. 1340): 2p5 = 5p5 6p [1/2]0 (J = 0) at 80 119 cm-1, 2p6 = 6p[3/2]2 (J = 2) at 79 212 cm-1, 2p9 = 6p[5/2]2 (J = 2) at 78 120 cm-1; excited at 249.6 nm (Sec. V and the abstract), and ‘250, 252, and 256 nm’ (p. 1341). The two-photon datasets’ abscissa is the level (a label).
WHAT IS TAKEN (tools/extract/kroll_1990.py). Table I’s two ‘This work’ rows: (1) the measured product sigma_tot G2(0), 7.0, 2.4, 4.0 x 10^-35 cm4 for 2p5, 2p6, 2p9: ‘The two-photon cross section as expressed in Eq. (1) is strictly the product of the actual two-photon absorption cross section and G2(0)’ (p. 1346); (2) sigma_tot, 5.0, 1.7, 2.9 x 10^-35 cm4, the same divided by G2(0) = 1.4, a value ‘previously determined’ for the second anti-Stokes line of the same laser system (ref. 27: D. J. Bamford, A. P. Hickman, M. J. Dyer and W. K. Bischel, J. Opt. Soc. Am. B 5, 1369 (1988)) and assumed for the first; ‘an educated guess might be that this quantity actually is slightly higher for the first than for the second anti-Stokes component. However, no conclusive evidence exists at present’ (p. 1346). DECISION: both are kept, because the measurement is the product and the correction rests on an assumed G2(0) whose uncertainty is not stated; the corrected values are the cross section proper and are primary, the product is a check (it carries the same measurement and must not be used beside them). The uncertainty, ‘30%’ (50 % for 2p9), is ‘one standard deviation based on 15 independent measurements for the 2p5 and 2p6 states and seven independent measurements for the 2p9 state’ (p. 1346); for sigma_tot it does not include G2(0). Table II’s measured photoionisation cross sections (10^-18 cm2): 2p5, 4.3 +- 0.7 (248 nm) and 1.9 +- 0.7 (193 nm); 2p6, 3.7 +- 0.7 and 1.8 +- 0.5; the level of the +- is not stated.
CHECKED (the script). sigma_tot G2(0) / 1.4 rounds to every printed sigma_tot. Sec. V (p. 1347) uses ‘two-photon absorption cross section sigma^(2) = 4.0 x 10^-45 cm4 s, and Doppler width 0.086 cm-1’ for 2p5: 7.0e-35 cm4 times the peak of a Gaussian of 0.086 cm-1 FWHM normalised in angular frequency, 2 sqrt(ln 2 / pi) / (2 pi c x 0.086 cm-1) = 5.80e-11 s, is 4.06e-45 cm4 s; with sigma_tot (5.0) it would be 2.9e-45. So Sec. V’s fractional-ionisation estimate (Fig. 8) uses the as-measured product, and Eq. (4)’s integral is over the angular frequency of the two-photon transition (‘omega_0 is the two-photon radial frequency’, p. 1342; the 0.086 cm-1 is xenon’s Doppler width at 80 119 cm-1 and 295 K, 0.0860): frequency_variable = angular. The ratio of the 2p5 and 2p6 values is 2.9 (‘~3’, p. 1347).
NOT TAKEN. Table I’s other experiments, as sigma_tot G2(0): ref. 10 (C. H. Chen, G. S. Hurst and M. G. Payne, Chem. Phys. Lett. 75, 473 (1980)), 6.1 for 2p5; ref. 8 (W. Gornik, S. Kindt, E. Matthias and D. Schmidt, J. Chem. Phys. 75, 68 (1981)), 6.8, 0.74, 3.7, ‘Factor of 3’; ref. 9 (T. D. Raymond, N. Bowering, C.-Y. Kuo and J. W. Keto, Phys. Rev. A 29, 721 (1984)), 2.7, 0.28, 1.3, ‘50%’. The paper does not say how they were brought to its definition (frequency variable, G2(0)), so the quantity’s required parameters cannot be stated for them; none is in the library. The theory of ref. 12 (M. S. Pindzola, M. G. Payne and W. R. Garrett, Phys. Rev. A 24, 3115 (1981)), a range ‘4-13’ for 2p5 (Dirac-Fock, ‘correct within a factor of 3-5’). Table II’s theory: ref. 13 (M. S. Pindzola, Phys. Rev. A 23, 201 (1981)), Hartree-Fock velocity to Dirac-Fock length ranges 1.3-3.0 (248 nm) and 0.7-1.8 (193 nm) for 2p5; ref. 14 (T. N. Chang and Y. S. Kim, Phys. Rev. A 26, 2728 (1982)), 3.7 and 1.8, an average over the 5p5 6p configuration; printed centred across both states’ columns; ranges and averages, not in the library. The 2p5/2p6 ratio of ‘5 +- 2’ from consecutive measurements only (p. 1347), kept in the notes. Figs. 1-8 (illustrations and model curves).
FINDINGS. dakka_2018 (Table I, ‘Literature’) compares its Kr sigma_0^(2) with this paper’s 2p6 value as 2.4 +- 0.8 x 10^-35 cm4: the as-measured product, not the G2-corrected 1.7. drag_2021 (Table 1) quotes the corrected values, 5.0, 1.7 and 2.9 x 10^-43 m4 (+-30, 30, 50 %), correctly converted (10^-35 cm4 = 10^-43 m4).
Recorded bibliographic identity status: VALIDATED. This concerns identification of the source; it does not establish the scientific correctness of its contents.
Datasets#
kroll_1990/sigma_tot_g2#
{
"id": "sigma_tot_g2",
"material": "Xe",
"file": "Xe/kroll_1990__sigma_tot_g2.csv",
"table": "tbl_3fbaf4afd365",
"quantity": "two_photon_excitation_cross_section",
"unit": "cm4",
"scale": 1e-35,
"abscissa": "label",
"use": "check",
"uncertainty": {
"relative": 0.3,
"relative_rows": {
"2p9": 0.5
},
"level": "1 sigma"
},
"parameters": {
"frequency_variable": "angular",
"polarization": "linear",
"photon_statistics": "as measured: the product sigma_tot G2(0), G2(0) of the first anti-Stokes beam of an H2 Raman shifter (not measured)",
"method": "two-photon-excited fluorescence, detection calibrated by H2 Raman scattering",
"definition": "sigma_tot = integral of the line-centre cross section sigma^(2)(omega - omega_0) d omega (Eq. 4), omega_0 the two-photon angular frequency, the line-centre value from Eq. (1); W = sigma^(2) Phi^2",
"levels": "2p5 = 5p5 6p[1/2]0 (J = 0), 2p6 = 6p[3/2]2 (J = 2), 2p9 = 6p[5/2]2 (J = 2)"
}
}
Table I (p. 1346), upper part, ‘This work’: sigma_tot G2(0), the measured product (Eq. 1 integrated over the line, Eq. 4). Rows: 2p5 (6p[1/2]0, 249.6 nm), 2p6 (6p[3/2]2, 252 nm), 2p9 (6p[5/2]2, 256 nm). A check: sigma_tot (primary) is this divided by an assumed G2(0) = 1.4. Uncertainty 30 % (2p9: 50 %), one standard deviation of 15 (2p9: 7) independent measurements.
kroll_1990/sigma_tot#
{
"id": "sigma_tot",
"material": "Xe",
"file": "Xe/kroll_1990__sigma_tot.csv",
"table": "tbl_3fbaf4afd365",
"quantity": "two_photon_excitation_cross_section",
"unit": "cm4",
"scale": 1e-35,
"abscissa": "label",
"use": "primary",
"uncertainty": {
"relative": 0.3,
"relative_rows": {
"2p9": 0.5
},
"level": "1 sigma"
},
"parameters": {
"frequency_variable": "angular",
"polarization": "linear",
"photon_statistics": "corrected, G2(0) = 1.4 assumed (measured for the second anti-Stokes line of the same laser, ref. 27; the light used is the first)",
"method": "two-photon-excited fluorescence, detection calibrated by H2 Raman scattering",
"definition": "sigma_tot = integral of the line-centre cross section sigma^(2)(omega - omega_0) d omega (Eq. 4), omega_0 the two-photon angular frequency, the line-centre value from Eq. (1) divided by G2(0); W = sigma^(2) Phi^2",
"levels": "2p5 = 5p5 6p[1/2]0 (J = 0), 2p6 = 6p[3/2]2 (J = 2), 2p9 = 6p[5/2]2 (J = 2)"
}
}
Table I (p. 1346), lower part, ‘This work’: sigma_tot, ‘assuming G2(0) = 1.4’ (note c), the as-measured product divided by 1.4 (checked). Rows: 2p5 (6p[1/2]0, 249.6 nm), 2p6 (6p[3/2]2, 252 nm), 2p9 (6p[5/2]2, 256 nm). The table gives no uncertainty for this part; the measurement’s 30 % (2p9: 50 %, one standard deviation) is recorded, without the unstated uncertainty of the assumed G2(0).
kroll_1990/photoionization_2p5#
{
"id": "photoionization_2p5",
"material": "Xe",
"file": "Xe/kroll_1990__photoionization_2p5.csv",
"table": "tbl_0a9507c3ebd9",
"quantity": "excited_state_photoionization_cross_section",
"unit": "cm2",
"scale": 1e-18,
"abscissa_unit": "nm",
"use": "primary",
"uncertainty": {
"column": true,
"level": "not stated"
},
"parameters": {
"initial_level": "2p5 (Paschen) = 5p5 6p[1/2]0, J = 0, two-photon excited from the ground state with linearly polarised light",
"method": "fluorescence depletion spectroscopy"
}
}
Table II (p. 1347), ‘Experiment (This work)’, 2p5 columns at 248 and 193 nm (KrF and ArF excimer lasers; the wavelengths as printed, to 1 nm). Fluorescence depletion, corrected by about 10 % for the non-uniform ionising fluence (Sec. III A). The +- is printed without a level.
kroll_1990/photoionization_2p6#
{
"id": "photoionization_2p6",
"material": "Xe",
"file": "Xe/kroll_1990__photoionization_2p6.csv",
"table": "tbl_0a9507c3ebd9",
"quantity": "excited_state_photoionization_cross_section",
"unit": "cm2",
"scale": 1e-18,
"abscissa_unit": "nm",
"use": "primary",
"uncertainty": {
"column": true,
"level": "not stated"
},
"parameters": {
"initial_level": "2p6 (Paschen) = 5p5 6p[3/2]2, J = 2, two-photon excited from the ground state with linearly polarised light (a single magnetic sublevel, p. 1344)",
"method": "fluorescence depletion spectroscopy"
}
}
Table II (p. 1347), ‘Experiment (This work)’, 2p6 columns at 248 and 193 nm (KrF and ArF excimer lasers; the wavelengths as printed, to 1 nm). Fluorescence depletion (Fig. 5 shows a 193 nm run giving 1.7e-18 cm2), corrected by about 10 % for the non-uniform ionising fluence (Sec. III A). The +- is printed without a level.
Formulas#
No formulas are recorded.
Corrections#
No dataset errata are recorded in this source record.
Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the review register for the checks and decisions.