tang_1989

X. Tang, A. L’Huillier and P. Lambropoulos, “Comment on ‘Laser-induced continuum structure in xenon’”, Phys. Rev. Lett. 62, 111 (1989)

Source record · Catalogue · Review register

DOI: 10.1103/PhysRevLett.62.111

Source kind: theory

Recorded technique: Comment on hutchinson_1988: a time-dependent calculation of the xenon laser-induced continuum structure with three discrete states, 5p6 (1S0) |g>, 5p5 6p (1S0) |a> and 5p5 10p (1S0) |b>, and three continua, including the paths hutchinson_1988 leaves out: the Raman coupling of 6p and 10p through the discrete states below the threshold and the ionisation of 6p by omega_d (Fig. 1(a)). Compared with one set of hutchinson_1988’s data (Fig. 1(b)).

Materials in structured entries: None recorded.

Dataset quantities: None recorded.

Contents: 0 datasets; 0 formulas.

Curation notes

Nothing extracted: no value of a quantity is printed. Phys. Rev. Lett. 62(1), 111 (2 January 1989) = PDF page 1; a scan, one image with a text layer. Identity checked against the page (journal, volume, number, date, title, authors, received 26 May 1988). The text and Fig. 1 were read from the rendered page.

WHAT IS ARGUED. (1) ‘the Raman coupling via the discrete states below the ionization threshold is as important as anything else in this problem, even though such discrete states are not near resonance’ (citing Dai and Lambropoulos 1987), against hutchinson_1988’s expectation that it is negligible in xenon. (2) The ionisation of 6p by omega_d, whose energy ‘falls between the two fine-structure thresholds [P3/2] and [P1/2] (which bracket a series of autoionizing resonances), and plays a crucial role’ (80 118.96 + 24 892.34 = 105 011 cm^-1, between 97 833.787 and 108 370.80 cm^-1; nist_asd_2026, with hutchinson_1988’s wavelengths read as vacuum ones). (3) Fig. 1(b): the calculation against the data at I_1 = 30 MW/cm^2 and I_d = 80 MW/cm^2 (hutchinson_1988’s Fig. 4(a), lower trace), against the detuning delta = E_a - E_b + hbar omega_1 - hbar omega_d with 2 hbar omega_1 = E_a - E_g, delta = 0 put at the centre of the measured main feature, the vertical scales matched at the background (‘The published experimental data did not contain a horizontal or a vertical scale’; hutchinson_1988’s figure has a 10 GHz bar but no absolute frequency). The calculated profile is a narrow dispersive feature at delta = 0 on the background; the data’s broad peak is at delta = 0 by construction, and the ‘shallow experimental minimum at delta ~ -23 GHz’ might be the calculated minimum if the peak is ‘extraneous to the effect sought’. ‘We have explored the entire range of intensities employed in the experiments without any appreciable effect on the discrepancy’; a q built from hutchinson_1988’s paths alone fits neither data nor calculation. (4) ‘ac Stark shifts were found negligible’ (in the calculation, at these intensities). (5) At 5-10 Torr the calculated ionisation of 65 % to 70 % ‘translates into 10^17 charges per cm^3’ (5 Torr at 295 K is 1.6 x 10^17 atoms/cm^3: consistent), with unknown effects; low pressure and absolute wavelength calibration are asked for.

WHAT BEARS ON OEP 8 (sections 4.3-4.4). (1) Bound-bound Raman couplings through far-detuned discrete states contribute to the real part of a continuum-mediated coupling as much as the continuum does (q), so a model that keeps only continuum terms for such a coupling is incomplete; knight_1990 (TC-989, Eq. 3.34) has the same structure. (2) The calculated light shifts of 6p[1/2]0 and 10p[1/2]0 at 30 and 80 MW/cm^2 are ‘negligible’ against the GHz structure: a statement, no number. (3) The calculated ionised fraction, 65-70 % for 12 ns pulses at 30 MW/cm^2 (249.63 nm) and 80 MW/cm^2 (401.73 nm), both colours together, is a validation target in principle for a (2+1) model through 6p[1/2]0, but the paper prints neither the 6p photoionisation cross section nor the two-photon coupling it used, nor the pulse areas (the pulse length and shape are hutchinson_1988’s).

NOT TAKEN. Fig. 1(b) (ionisation probability against detuning, calculation and re-plotted data): a line shape, not a quantity; the data are hutchinson_1988’s re-scaled. Further data cited, not in the library: Bo-nian Dai and P. Lambropoulos, Phys. Rev. A 36, 5205 (1987) (Raman coupling in LICS, Na). The reply is hutchinson_1989.

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

Datasets

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Formulas

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Corrections

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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.