talebpour_1998

A. Talebpour, S. Larochelle and S. L. Chin, “Suppressed tunnelling ionization of the D2 molecule in an intense Ti:sapphire laser pulse”, J. Phys. B: At. Mol. Opt. Phys. 31, L49 (1998)

Source record · Catalogue · Review register

DOI: 10.1088/0953-4075/31/2/003

Source kind: measurement

Recorded technique: Ion yields against peak intensity of Ar+, D2+ and D+ in 200 fs, 800 nm, linearly polarised Ti:sapphire pulses (the technique of Talebpour, Chien & Chin, J. Phys. B 29, 5725 (1996), not described here), compared with the PPT rate (Eq. (2)) integrated over the pulse and the focal volume. For D2, a one-dimensional quasi-classical barrier along the field through one proton, in the single-active-electron potential built from Coulson’s (1938) one-electron wavefunction (Eqs. (6)-(8)), defines an angle-dependent effective charge Z_eff(theta) with the same barrier integral as an atom (Eqs. (9)-(10)); the PPT rate with Z_eff(theta) is averaged over the hemisphere (Eq. (11)) and weighted by Franck-Condon factors (Dunn 1966) (pp. L50-L56).

Materials in structured entries: D2

Dataset quantities: ionization_model_parameter

Contents: 1 dataset; 0 formulas.

Curation notes

PDF pages 1-11: page 1 is the IOPscience download cover, PDF p. 2 = journal p. L49 (pages cited are journal pages). Identity checked on the first page. The library’s title field has lost ‘D2’ (‘Suppressed tunnelling ionization of the molecule’); the paper is about D2, not O2 (the guess in the list of requested papers): O2 does not appear in it.

EXTRACTED: zeff_D2, the orientation-averaged effective charge 0.72 (p. L56), an ionization_model_parameter of the PPT rate (Eq. (2)), use = check as talebpour_1999’s charges are. It is computed, not fitted: Z_eff(theta) from Eq. (9) at 1.5e14 W/cm^2 (its intensity dependence over 3e13-4e14 W/cm^2 is ‘weak (less than 5% deviation from the mean value)’, p. L55), W_PPT(theta) from Eq. (2), and the hemispherical average of Eq. (11); ‘the TI rate of the D2 molecule is the same as that of an atom with a similar ionization potential, and with Z_eff = 0.72’ (p. L56). With the Franck-Condon average the PPT yield agrees with the measured S(D2+) + 0.5 S(D+) (‘The agreement with experiment is excellent’, p. L56; Fig. 2). No uncertainty is stated. solprop has no effective charge for H2 or D2 (it uses MO-ADK for them); talebpour_1999’s N2 (0.9) and O2 (0.53) charges come from the same group and the same PPT form.

THE PPT FORM (Eq. (2), p. L50, checked on the page image): W_PPT = |C_n*l*|^2 f_lm E_i sqrt(6/pi) (2(2E_i)^(3/2)/F)^(2n* - |m| - 3/2) (1 + gamma^2)^(|m|/2 + 3/4) A_m(omega, gamma) exp(-(2(2E_i)^(3/2)/(3F)) g(gamma)), n* = Z_eff/sqrt(2E_i); g(gamma) Eq. (3) as ilkov_1992; f_lm Eq. (4); |C_n*l*|^2 = 2^(2n*)/(n* Gamma(n* + l* + 1) Gamma(n* - l*)) (Eq. (5)); A_m ‘can be found in Perelomov et al (1966) and Ilkov et al (1992)’; ‘This rate should be averaged over the different values of m’ (p. L51). The same form as larochelle_1998’s Eq. (10). Against ilkov_1992 Eq. (8) (corrected prefactor), it lacks the factor (1 + gamma^2)^(-n*) (ilkov_1992 has (2F0/(F sqrt(1 + gamma^2)))^(2n - |m| - 3/2) = (2F0/F)^(2n - |m| - 3/2) (1 + gamma^2)^(-n + |m|/2 + 3/4)): at gamma = 1 a factor 2^(-n*) (about 0.5 for n* ~ 0.94) between the two. l* and the l, m used for D2 are not stated.

OTHER VALUES (text, not taken): the ionisation potentials used, D2 15.46 eV and Ar 15.76 eV (p. L50, uncited); Ti:sapphire frequency 0.057 au; the rotation frequency omega_0 = (alpha F^2/(mu R^2))^(1/2) of D2 at 1e14 W/cm^2, 7.9e-4 au, a period 453 laser periods against ~70 in the pulse, so the molecules are randomly oriented (Eq. (1), Sukharev & Krainov, p. L50); the potential in Fig. 3 at F = 0.06 au and 20 degrees, the electron’s ionisation energy 0.57 au (p. L53); Coulson’s wavefunction, Eq. (7), Psi(xi, eta) = 0.877 58 e^(-0.75 xi) (1 + 0.277 87 eta^2 - 0.128 63 xi + 0.012 503 xi^2 - 0.039 589 xi eta^2), xi = (r1 + r2)/R, eta = (r1 - r2)/R (p. L53; R not stated). ‘The ion signal [of D2] is 40 times lower than the ion signal of Ar’ (p. L52). NO+ (not curated): Z_eff = 2.2 with the -RF term ‘is capable of fitting the experimental results’ of Talebpour et al. 1997c (p. L57), and the earlier ~7 eV reduction of NO+’s ionisation potential is withdrawn (p. L57).

FIGURES (not digitised): Fig. 1, Ar+, D2+ and D+ yields against intensity with the PPT Ar+ curve (the upper scale gamma of Ar); Fig. 2, S(D2+) + 0.5 S(D+) with PPT curves for Z = 1, 0.72, and 0.72 with Franck-Condon factors; Figs. 3-5, the potential; Fig. 6, Z_eff(theta) and W_PPT(theta) at 1.5e14 W/cm^2.

Recorded bibliographic identity status: VALIDATED_WITH_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.

Datasets

talebpour_1998/zeff_D2

{
  "id": "zeff_D2",
  "material": "D2",
  "table": "text",
  "quantity": "ionization_model_parameter",
  "unit": "1",
  "abscissa": "none",
  "use": "check",
  "parameters": {
    "model": "ppt",
    "parameter": "Z_eff",
    "wavelength_nm": 800,
    "intensity_w_per_cm2": 150000000000000.0
  }
}

1 inline points in the source record.

p. L56: the orientation-averaged effective charge of the PPT rate (Eq. (2)) for D2 (E_i = 15.46 eV), from Z_eff(theta) computed with Eqs. (8)-(10) at 1.5e14 W/cm^2, 800 nm, and the hemispherical average of W_PPT(theta) (Eq. (11)). Computed, not fitted (record notes); the l and m used are not stated. No uncertainty is stated.

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.