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 · Catalogue · 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 <f|e.mu|k><k|e.mu|g> / (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 |<z>|^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

{
  "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 review register for the checks and decisions.