bokor_1980#
J. Bokor, J. Zavelovich and C. K. Rhodes, “Multiphoton ultraviolet spectroscopy of some 6p levels in krypton”, Phys. Rev. A 21, 1453-1459 (1980)
Source record · Catalogue · Review register
Source kind: measurement
Recorded technique: Two-photon excitation of Kr 4p5 6p[1/2]0 and 6p[3/2]2 by an ArF* laser line-narrowed and tuned by two intracavity fused-silica prisms (192.7-194.0 nm, up to 30 mJ, 13 ns, bandwidth 0.1 nm, ‘our measured laser linewidth of 25 cm-1’), wavelength calibrated on the O2 Schumann-Runge absorptions, focused by a 90 mm CaF2 lens into a stainless-steel cell; the 6p -> 5s fluorescence (427.4 nm from 6p[3/2]2, 437.6 nm from 6p[1/2]0) collected at right angles onto a 0.3 m spectrometer with an optical multichannel analyser, or time resolved with a photomultiplier and transient digitiser (pp. 1453-1454). The photoionisation cross section of 6p[3/2]2 from the saturation of the fluorescence with the laser intensity at 5 torr (Eqs. 7-12, Fig. 4), with the measured lifetime and self-quenching rate.
Materials in structured entries: Kr
Dataset quantities: excited_state_photoionization_cross_section
Contents: 2 datasets; 0 formulas.
Curation notes#
Phys. Rev. A 21(5), 1453-1459 (May 1980) = PDF pages 1-7 (journal page = PDF page + 1452); a scan with a text layer. Identity checked against the first page (PHYSICAL REVIEW A VOLUME 21, NUMBER 5, MAY 1980; received 6 November 1979; Bokor at Stanford, Zavelovich and Rhodes at Chicago Circle) on 2026-10-08. Every number below was read on the rendered pages (pp. 1455, 1457, 1458) and Table I’s image.
WHAT IS TAKEN. (1) The measured photoionisation cross section of 4p5 6p[3/2]2 at the laser wavelength, ‘(3.2 +- 2.0) x 10^-19 cm2’ (abstract; p. 1457), from the slope and intercept of I / N* against 1 / I (Eq. 11, Fig. 4), sigma_pi = (beta / m) hbar omega (1 / tau_rad + k_q N0)^-1 (Eq. 12), independent of the two-photon rate and of the absolute excited density. ‘The major source of uncertainty in this experiment arises from the conversion of the measured laser output energy to the actual intensity at the laser focus’ (a multimode beam, the focal spot from geometrical optics); a ‘systematic increase ... in the range of 10-20%’ for the 10 % rise and fall times of the pulse ‘has been incorporated’. The +-2.0 has no stated level. The laser was at the 6p[3/2]2 line centre, which Table I places at 193.49 nm; the abstract and conclusions say ‘at 193 nm’. (2) The quantum-defect estimate, ‘at lambda = 193.5 nm as sigma_pi = 1.8 x 10^-19 cm2’ (Eq. 13, p. 1458), ‘in good agreement with the experimentally determined value’: a check (the paper does not print its U_I; with khambatta_1988’s U_I = 1.1805 eV Eq. 13 gives 1.70 x 10^-19 at 193.5 nm). Krypton two-photon ionisation (OEP 6, Q2): the paper has none.
NOT TAKEN: TABLE I (p. 1455), ‘Estimates of two-photon excitation parameters’, the two-photon coupling parameter alpha (10^-31 cm4/W) of 6p[1/2]0 (192.75 nm) and 6p[3/2]2 (193.49 nm), 2.62 and 2.34, single-path estimates through 5s[3/2]1 (mu_1 = 1.39 D from f = 0.219; mu_2 = 0.806 and 0.763 D from the measured lifetimes and branching ratios; detuning 29 000 cm-1). alpha is defined by W = alpha I^2 / hbar omega = 2! (2 pi)^3 / (hbar c)^2 I^2 |M|^2 g(omega) (Eq. 1), with g = 0.939 / (2 Delta omega_L^2 + Delta omega_D^2)^(1/2) on resonance (Eq. 5) for the 25 cm-1 laser: a line-centre coefficient of this laser, including the factor 2! of chaotic light, not the frequency-integrated cross section. Checked: Eqs. (1) and (5) with the table’s mu and 29 000 cm-1 give 2.73 and 2.44 x 10^-31, both 4.1 % above the printed values (consistent with a detuning near 29 600 cm-1). In khambatta_1988’s convention (the same g, G^(2) = 2) the 6p[3/2]2 value corresponds to sigma_0^(2) = alpha hbar omega / (2 g) = 8.5 x 10^-37 cm4 (6p[1/2]0: 9.6 x 10^-37), with g = 1.41 x 10^-13 s: derived here, not printed, so not data; it agrees with khambatta_1988’s own single-path 8.7 x 10^-37 (the same matrix elements: its mu_2 = 0.382 D enters doubled). Table II’s lifetimes (123 +- 5 and 115 +- 5 ns) and the self-quenching rates ((4.1 +- 0.4) and (6.7 +- 0.7) x 10^-10 cm3/s): no quantity. The measured ratio of the 437.6 and 427.4 nm fluorescence at line centre, 0.45 against a predicted 0.42 (p. 1458): not a quantity here. Figs. 2-4 (spectra, decay rates, saturation): their numbers are the printed results above.
QUOTED ELSEWHERE, CHECKED. geohegan_1986 (TC-886) quotes ‘Bokor et al.’ for the 6p[3/2]2 photoionisation cross section, 3.2 x 10^-19 cm2: matches. It quotes Bokor and co-workers and Bischel et al. for alpha of 6p[3/2]2, ‘(1-2.3) x 10^-31 cm4 W-1’, ‘Assuming a 100-cm-1-bandwidth ArF laser’: this paper’s 2.34 is for its measured 25 cm-1 (Eq. 5 and p. 1455), not 100 cm-1 (a fourfold difference in g). The 100 cm-1 is Bischel et al.’s: bischel_1979’s estimate for Kr 4p5 6p is 1 x 10^-31 cm4/W for a 100 cm-1 line, so only the lower end of the quoted range is for 100 cm-1. khambatta_1988 quotes alpha = 2.34 x 10^-31 cm4/W and sigma_pi = (3.2 +- 2.0) x 10^-19 cm2: both match.
TWO-PHOTON DATA CITED, NOT IN THE LIBRARY: D. J. Kligler, J. Bokor and C. K. Rhodes, Phys. Rev. A 21, 607 (1980) (H2 E,F photoionisation by the same method); B. R. Marx, J. Simons and L. Allen, J. Phys. B 11, L273 (1978) (the line-shape factor); R. T. Hawkins, H. Egger, J. Bokor and C. K. Rhodes, Appl. Phys. Lett. 36, 391 (1980) (Xe 6p[1/2]0 two-photon excitation with KrF). The paper’s Ref. 5, W. K. Bischel, J. Bokor, D. J. Kligler and C. K. Rhodes, IEEE J. Quantum Electron. QE-15, 380 (1979), is curated as bischel_1979; its Ref. 11, H. A. Hyman, Appl. Phys. Lett. 31, 14 (1977) (calculated photoionisation of the first excited s and p states of Kr and Ar), as hyman_1977.
Recorded bibliographic identity status: VALIDATED_WITH_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.
Datasets#
bokor_1980/sigma_pi_6p32_2#
{
"id": "sigma_pi_6p32_2",
"material": "Kr",
"table": "text",
"scale": 1e-19,
"quantity": "excited_state_photoionization_cross_section",
"unit": "cm2",
"abscissa_unit": "nm",
"use": "primary",
"uncertainty": {
"column": true,
"level": "not stated"
},
"parameters": {
"initial_level": "4p5 6p[3/2]2, J = 2, two-photon excited from the ground state by the same (linearly polarised) light",
"method": "saturation of two-photon-excited fluorescence by excited-state photoionisation, rate equations with a square pulse (Eqs. 7-12)"
}
}
1 inline points in the source record.
Abstract and p. 1457: the photoionisation cross section of 4p5 6p[3/2]2 at the excitation wavelength, (3.2 +- 2.0) x 10^-19 cm2, from the saturation of the 427.4 nm fluorescence with the laser intensity (Eqs. 11, 12; Fig. 4) at 5 torr of Kr, with the measured tau_rad = 115 ns and k_q = 6.7e-10 cm3/s; includes a 10-20 % correction for the pulse shape. x is the 6p[3/2]2 two-photon line centre as Table I prints it (the text: ‘193 nm’; the wavelength medium is not stated, recorded as vacuum, the default). The +- has no stated level; it is mostly the focal intensity.
bokor_1980/sigma_pi_6p_quantum_defect#
{
"id": "sigma_pi_6p_quantum_defect",
"material": "Kr",
"table": "text",
"scale": 1e-19,
"quantity": "excited_state_photoionization_cross_section",
"unit": "cm2",
"abscissa_unit": "nm",
"use": "check",
"uncertainty": {
"level": "not stated"
},
"parameters": {
"initial_level": "4p5 6p (the level as the paper names it here; the measurement is of 6p[3/2]2)",
"method": "quantum-defect approximation, sigma = 8e-18 / [Z (U_I / R)^(1/2) (h nu / U_I)^3] cm2 (Eq. 13, Lorents, Eckstrom and Huestis 1973)"
}
}
1 inline points in the source record.
p. 1458: the quantum-defect (hydrogenic) estimate of ‘the 6p level in krypton at lambda = 193.5 nm’, Eq. (13); the binding energy used is not printed. A model value.
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.