kligler_1978 ============ D\. Kligler, D\. Pritchard, W\. K\. Bischel and C\. K\. Rhodes, "XeO\* production through collisional electronic energy transfer from two\-photon excited Xe atoms", J\. Appl\. Phys\. 49, 2219\-2223 \(1978\) `Source record `__ · :doc:`Catalogue ` · :doc:`Review register ` DOI: `10\.1063/1\.325127 `__ **Source kind:** measurement **Recorded technique:** Xe/N2O mixtures \(6000\:1 to 500\:1, 0\-760 Torr\) irradiated by a transverse\-discharge KrF\* laser at 248\.4 nm \(20\-30 mJ, 15 ns; the laser's bandwidth is not stated\), focused by a 50 mm lens to 0\.2 x 0\.3 mm, 'a peak focused power of 3 x 10^9 W/cm^2'; the XeO\* \(and O\(1S\)\) emission at 520\-570 nm through 10 nm filters on a cooled photomultiplier \(photon counting\); the square\-law dependence on laser energy \(Fig\. 3\), decay rates and yields against pressure \(Fig\. 4\)\. Sec\. IV and Table I\: estimates of two\-photon couplings from second\-order perturbation theory \(Eqs\. 2\-3, Ref\. 14\: Bischel, Kelley and Rhodes 1976\) with one intermediate state, mu\_1^2 and mu\_2^2 of order 1 D^2, an energy denominator and an estimated linewidth\. **Materials in structured entries:** Xe **Dataset quantities:** multiphoton\_ionization\_cross\_section **Contents:** 1 dataset; 0 formulas. Curation notes -------------- J\. Appl\. Phys\. 49\(4\), 2219\-2223 \(April 1978\) = PDF pages 2\-6 \(PDF page 1 is the AIP download cover; journal page = PDF page \+ 2217\)\. Identity checked on the first page of the article \(PDF p\. 2\: title, authors, Molecular Physics Center, SRI International; received 26 September 1977, accepted 9 November 1977\) on 2026\-10\-09\. Every number below was read on the rendered pages \(pp\. 2220\-2223\) and Table I's cells against its image\. WHAT THE PAPER MEASURES FOR XENON\: A LOWER BOUND, NOT A STRENGTH\. From the largest XeO\* signal \(2\.5 x 10^16 cm^\-3 N2O in 2\.5 x 10^19 cm^\-3 Xe, 'about 1\.6 x 10^6 counts', detection efficiency 'about 0\.2 %', so '8 x 10^8 photons'\), a peak duration of 8 ns and a focal volume of 2 x 10^\-4 cm^3, 'excited Xe must be produced in the focal volume at a rate not less than R\_Xe = 5 x 10^20 cm^\-3 sec^\-1'; with R\_Xe = sigma\_Xe \(I / hbar omega\) n\_Xe \(Eq\. 1\), 'sigma\_Xe \>= 5 x 10^\-27 cm^2 at our intensity' \(p\. 2220\), 'where the unit branching ratio was assumed' \(p\. 2222\)\. The script recomputes every step \(5\.3 x 10^\-27 cm^2\)\. This is a bound on the production of unresolved 'Xe\*' \(5p5 6p, 5p5 6s or Xe2\*, any of which may feed XeO\*, p\. 2221\) by a laser whose bandwidth the paper does not give, at 248\.4 nm\: the 6p\[1/2\]0 two\-photon resonance is at 249\.63 nm \(hawkins\_1980\), 396 cm^\-1 away on the two\-photon scale \(NIST 80118\.962 cm^\-1\)\. Above 100 Torr the yield grows as the 2\.6 power of pressure \(p\. 2221\)\. NOT TAKEN\: no quantity holds a lower bound on an intensity\-dependent effective cross section of unresolved products; it is not a per\-level two\_photon\_excitation\_cross\_section\. As sigma/I it is \>= 1\.8 x 10^\-36 cm^4/W; as sigma\_2 = sigma / Phi, \>= 1\.4 x 10^\-54 cm^4 s \(computed\)\. WHAT IS TAKEN \(tools/extract/kligler\_1978\.py\)\: Table I's Xe\+ row \(1930 Angstrom, two\-photon ionisation\), sigma/I = 1 x 10^\-34 cm^4/W, an estimate \(use = check\), as bischel\_1979 \(TC\-917\) holds the same estimate \(equal; the script checks\)\. NOT TAKEN \(no quantity holds them\)\: Table I's bound two\-photon excitation estimates of sigma/I \(cm^4/W\), at line centre for an 'Estimated linewidth' of 10^6 MHz \(footnote b\)\: H2 E,F \(v = 2, j = 2\) 1\.8 x 10^\-31, CO F 1\.6 x 10^\-32, N2 E 1\.1 x 10^\-33, Kr\* 4p5 6p \(103,762 cm^\-1\) 3 x 10^\-31, I2 1\.7 x 10^\-30 at 1930 Angstrom; Xe\*\(5p5 6p\) 3 x 10^\-31 and N2O ~3 x 10^\-35 \(linewidth ~10^9 MHz\) at 2484 Angstrom\. They are linewidth\-dependent peak coefficients, not the frequency\-integrated two\_photon\_excitation\_cross\_section, and the line shape g\(omega\) is not stated \(as bischel\_1979\)\. The text's 'sigma ~ 10^\-21 cm^2' for Xe at 3 x 10^9 W/cm^2 is Table I's 3 x 10^\-31 times that intensity \(checked\)\. The N2O bound sigma\_N2O \<= 8 x 10^\-25 cm^2 and the N2O estimate sigma\_2 ~ 6 x 10^\-26 cm^2 \(Eq\. 4\); the XeO\* quenching rate coefficients k\_N2O = 2\.3\(4\) x 10^\-11 and k\_Xe = 0\.4\(1\) x 10^\-14 cm^3/s \(p\. 2221; XeO\* is not a level of a material\); the Xe\* \-\> Xe2\* conversion 'at 800 Torr \.\.\. 125 x 10^5 sec^\-1, see Ref\. 13' \(a quoted rate of an unspecified level at one pressure\); Figs\. 2\-4 \(spectra, counts and decay rates of XeO\*\)\. THE ESTIMATE AND THE PER\-LEVEL CONVENTION \(findings; the script prints them\)\. Eq\. \(2\), sigma\(omega\) = \[\(2 pi\)^2 / hbar c^2\] I omega \|M\_fg\|^2 g\(omega\), with M\_fg = 2 sum\_k \\ / \(E\_kg \- hbar omega\) \(Eq\. 3\), 'omega is the laser angular frequency', 'g\(omega\) is the linewidth factor' \(form and normalisation not stated\)\. With Table I's inputs \(one intermediate state, mu^2 = 1 D^2, Delta = 28 x 10^3 cm^\-1, 2484 Angstrom, 10^6 MHz\) Eq\. \(2\) in CGS gives 2\.6 x 10^\-31 cm^4/W for a Lorentzian g normalised in the ordinary frequency \(3\.8 x 10^\-31 Gaussian\), 4\.1 and 6\.1 x 10^\-32 normalised in the angular frequency\: the printed 3 x 10^\-31 matches the first reading; so do Kr \(2\.9 against 3\), N2 \(1\.05 against 1\.1\) and I2 \(1\.64 against 1\.7\); H2 gives 1\.3 against 1\.8, and Xe\+ \(10^9 MHz\) 1\.0 x 10^\-33 against the printed 1 x 10^\-34\. In TC\-952's convention \(sigma\_0 = 2 pi^3 alpha^2 a0^4 omega\_au^2 delta^TP, profile normalised in the two\-photon angular frequency, coherent light\) the same inputs give delta^TP = \|M\|^2 = 5\.89 au \(M = 2\.43 au; for J = 0 \-\> 0 and parallel linear polarisation the tensor is isotropic and delta^TP = \|S\_zz\|^2\) and sigma\_0 = 5\.1 x 10^\-37 cm^4; converting the printed 3 x 10^\-31 cm^4/W with a 10^6 MHz Lorentzian \(FWHM, two\-photon frequency; assumed\) gives sigma\_0 = 2\.4 x 10^\-36 cm^4 \(delta^TP = 27 au; Gaussian 1\.6 x 10^\-36, 19 au\)\. The factor 4\.6 between the two is Eq\. \(2\)'s prefactor, \(2 pi\)^2 against 2 pi^3, times 2 pi for the ordinary\-frequency normalisation, and the rounding to 3\. Either way the estimate is 20 to 100 times below kroll\_1990's \(TC\-890\) measured 5\.0 x 10^\-35 cm^4 \(580 au\) and henriksson\_2005's \(TC\-888\) 752 au for 6p\[1/2\]0\: it uses placeholder moments \(1 D^2; the NIST 5p6 \-\> 6s\[3/2\]1 f = 0\.265 corresponds to \|\\|^2 = 2\.8 D^2\) and one intermediate state, and the paper calls it an estimate\. Inputs\: Table I and Eqs\. \(2\)\-\(3\) \(printed\); the line shape \(assumed\); NIST's level energy \(curated\)\. Neither number is a third measurement of the 6p\[1/2\]0 strength\. FINDINGS \(held records\)\. bischel\_1979 \(same group, 1979\)\: its Table I's Xe\+ value, 1 x 10^\-34 cm^4/W at 193 nm, equals this paper's \(script\); its bound rows use a 100 cm^\-1 \(3 x 10^6 MHz\) laser line where this paper's use 10^6 MHz, and its Xe 6p \(8 x 10^\-32\) and Kr 6p \(1 x 10^\-31\) values are this paper's 3 x 10^\-31 scaled by the linewidth ratio \(1/3, 1/3\.75\)\. bischel\_1979's DOUBT that its Table I's Kr level '103,762 cm^\-1' is a misprint of the text's '103 363' is answered here\: Table I's 103,762 cm^\-1 is NIST's Kr 4p5 6p\[1/2\]0 \(103761\.634 cm^\-1\), the Kr analogue of Xe 6p\[1/2\]0, and 103 363 is 6p\[3/2\]2 \(103362\.612\)\: two real levels, no misprint\. lehmberg\_1995 uses the same 248\.4 nm and places 6p\[1/2\]0 at 249\.6 nm \(80119 cm^\-1\), as this paper \(80119 cm^\-1, p\. 2222\)\. Sec\. V's 'Kr\(4p5 5p\)' \(p\. 2222\) is a slip for Table I's 4p5 6p\. DOUBT\: footnote \(g\) of the linewidth '~10^9' \(Xe\+ and N2O\) reads 'Some interfering absorption present from Cordes bands\. See J\.A\. Myer, J\. Chem\. Phys\. 52, 716 \(1970\)'\: Cordes bands are bands of I2, and bischel\_1979's footnote \(g\) for the same cells reads 'Estimated for photoionization continuum'\. The footnote text appears misplaced; no value depends on it\. TWO\-PHOTON DATA CITED, NOT IN THE LIBRARY\: W\. K\. Bischel, P\. J\. Kelley and C\. K\. Rhodes, Phys\. Rev\. A 13, 1817 \(1976\) \(Eq\. 2, Ref\. 14\) and Phys\. Rev\. A 13, 1829 \(1976\) \(Ref\. 5\); D\. J\. Kligler and C\. K\. Rhodes, Phys\. Rev\. Lett\. 40, 309 \(1978\) \(H2 E,F two\-photon excitation at 193 nm, Ref\. 17\)\. **Recorded bibliographic identity status:** VALIDATED\_WITH\_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents. Datasets -------- kligler\_1978/sigma\_over\_I\_Xe ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. code-block:: text { "id": "sigma_over_I_Xe", "material": "Xe", "file": "Xe/kligler_1978__sigma_over_I_Xe.csv", "table": "tbl_51477d804fd7", "quantity": "multiphoton_ionization_cross_section", "unit": "cm4 W-1", "scale": 1e-34, "abscissa_unit": "angstrom", "use": "check", "uncertainty": { "level": "not stated" }, "parameters": { "photons": 2, "polarization": "not stated", "method": "estimate from second-order perturbation theory with one intermediate state (Eqs. 2-3): energy denominator 16 x 10^3 cm^-1, mu_1^2 = mu_2^2 = 1 debye^2, linewidth ~10^9 MHz", "definition": "R = sigma (I / hbar omega) n (Eq. 1, p. 2220); Table I's sigma/I in cm^4/W", "wavelength_nm": 193, "linewidth_mhz": 1000000000.0, "linewidth_definition": "'~10^9 (g)' (Table I); footnote (g) reads 'Some interfering absorption present from Cordes bands' (record notes)", "energy_denominator_cm1": 16000 } } Table I \(p\. 2222\), xenon, 1930 Angstrom \(ArF\*\), excited product Xe\+\: the estimated sigma/I in cm^4/W \(rate per atom \(sigma/I\) I^2 / hbar omega, Eq\. 1; sigma\_2 = \(sigma/I\) hbar omega = 1\.03e\-52 cm4 s at 193\.0 nm\), energy denominator 16 x 10^3 cm^\-1, linewidth ~10^9 MHz, mu\_1^2 = mu\_2^2 = 1 D^2\. One significant figure; an order\-of\-magnitude estimate\. Equal to bischel\_1979's later copy of the same estimate\. Eq\. \(2\) with these inputs gives 1\.0e\-33 for a 10^9 MHz Lorentzian normalised in the ordinary frequency, ten times the printed value \(record notes\)\. 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 :doc:`review register ` for the checks and decisions.