crance_1985
===========

M\. Crance and M\. Aymar, "Two\-photon detachment of H\-\. A model calculation", J\. Phys\. B\: At\. Mol\. Phys\. 18, 3529\-3536 \(1985\)

`Source record <https://github.com/LupoLab/optmat/blob/main/src/optmat/data/sources/crance_1985.toml>`__ · :doc:`Catalogue </the-data/sources>` · :doc:`Review register </register>`

DOI: `10\.1088/0022\-3700/18/17/014 <https://doi.org/10.1088/0022-3700/18/17/014>`__

**Source kind:** theory

**Recorded technique:** One\- and two\-photon detachment of the H\- ground state in the dressed\-atom picture \(atom plus quantised field, Eqs\. 1\-5\), linear polarisation, dipole approximation, a real Hamiltonian in a basis of complex square\-integrable two\-electron functions \(Eq\. 6, \(lambda r e^\(\-i theta\)\)^\(l\+n\) exp\(\-lambda r e^\(\-i theta\)/2\), several theta in 0\-pi/2\: the complex\-basis equivalent of complex scaling\)\. The complex energy of the perturbed ground state is followed with the field; its imaginary part gives the detachment probability, sigma^\(1\) = 2 Im\(E\_g\) / hbar I \(Eq\. 16\) and sigma^\(2\) = 2 Im\(E\_g\) / hbar I^2 \(Eq\. 18\), the basis restricted to the multiplicities that give Im\(E\_g\) to fourth order in the field \(lowest\-order perturbation theory in the field, configuration interaction treated non\-perturbatively\)\. Ground state\: ss', pp', dd' 1S configurations \(n\_s = 6, n\_p = n\_d = 5\), E\_g = \-0\.5273 au against Pekeris's \-0\.5277 \(Table 1\)\. Two\-photon final states 1S and 1D \(ss', p2, d2, sd'\), between the three\-photon and one\-photon detachment thresholds, E\_A/2 \< hbar omega \< E\_A \(Eq\. 17\); 'about 15% for two\-photon processes' from enlarging the basis \(p\. 3534\)\.

**Materials in structured entries:** None recorded.

**Dataset quantities:** None recorded.

**Contents:** 0 datasets; 0 formulas.

Curation notes
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J\. Phys\. B\: At\. Mol\. Phys\. 18, 3529\-3536 \(1985\) = PDF pages 2\-9 \(PDF page 1 is the IOPscience cover sheet; journal page = PDF page \+ 3527\)\. Identity checked on PDF pages 1\-2 \(the cover\: '1985 J\. Phys\. B\: At\. Mol\. Phys\. 18 3529'; the title page\: Michele Crance and Mireille Aymar, Laboratoire Aime Cotton, Orsay; received 4 February 1985\) on 2026\-10\-09\. The pages are scanned images \(2076 x 2945 pixels\) with a text layer\.

NOTHING TAKEN\. The paper is about the negative hydrogen ion, H\-, which the material registry does not hold \(no anion is registered; 'ion' is a gas\-phase cation, TC\-440\), and the vocabulary's quantities are for the neutral gases and their cations\. Its numbers\: Table 1 \(p\. 3533\), ground\-state expectation values of H\- \(E\_g, \<r\_1\>, \<r\_1^2\>, \<r\_12^2\> in au; this work \-0\.5273, 2\.70, 11\.66, 24\.7 against Pekeris \-0\.5277, 2\.71, 11\.91, 25\.2; checked against the table image\), no quantity; Fig\. 1 \(p\. 3534\), the one\-photon detachment cross section of H\- for 0\.03 \< omega \< 0\.10 au against Smith and Burch's measurements and Chandrasekhar's and Broad and Reinhardt's calculations \(raster\); Fig\. 2 \(p\. 3535\), log\-log, the two\-photon detachment cross sections sigma\_s^\(2\), sigma\_d^\(2\) \(final 1S and 1D\) and their total, in s^\-1 \(W cm^\-2\)^\-2, against the photoelectron energy epsilon = 2 hbar omega \- E\_A \(Eq\. 20\) in cm^\-1 \(about 70 to 3500 cm^\-1\), 1e\-13 to 1e\-10 \(raster; the abstract\: 'between 0 and 10^\-10 s^\-1 \(W cm^\-2\)^\-2'\); near threshold sigma\_s ~ epsilon^\(1/2\) and sigma\_d ~ epsilon^\(5/2\) \(O'Malley's threshold law, drawn as dashed lines\), sigma\_s largest near omega = 0\.019 au \(p\. 3535\)\.

WHY IT IS HERE\. It is cited among the two\-photon references of the curated records\: pan\_1990b \(TC\-908; its Ref\. 16, with Fink and Zoller, for the negative hydrogen ion, p\. 6271\) and starace\_1987 \(TC\-878; its Ref\. 19\), both listed under 'H\-' in those records' notes, and nikolopoulos\_2001 \(below\)\. bachau\_1990 \(TC\-905\) does not cite it \(its Ref\. 6 is Crance's chapter in Chin and Lambropoulos's book\)\. It is a method reference\: two\-photon detachment of a two\-electron system by a dressed\-atom complex\-basis calculation, an L^2 basis with complex exponents only for the continua that carry a pole and real functions elsewhere \(Sec\. 2\.2, pp\. 3531\-3532\)\.

FINDING \(a citation elsewhere\)\: nikolopoulos\_2001 \(TC\-875, its notes\) quotes 'Crance and Aymar, J\. Phys\. B 18, 3529 \(1985\)' for two\-photon DOUBLE ionisation cross sections of helium, 2\.05, 1\.74 and 1\.73 x 10^\-55 cm4 s at 43\.5, 45 and 46\.25 eV, as Nikolopoulos and Lambropoulos's paper prints that reference \(its p\. 559 and reference list\)\. This paper, at that volume and page, is the H\- detachment calculation above\: it contains no helium values and no double ionisation\. The helium values' true source is not identified here\.

**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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No datasets are recorded.

Formulas
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No formulas are recorded.

Corrections
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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 </register>` for the checks and decisions.