title: XUV free-electron laser desorption of NO from graphite (0001).
abstract: We report results of femtosecond laser induced desorption of NO from highly oriented pyrolytic graphite using XUV photon energies of hν = 38 eV and hν = 57 eV. Femtosecond pulses with a pulse energy of up to 40 μJ and about 30 fs duration generated at FLASH are applied. The desorbed molecules are detected with rovibrational state selectivity by (1 + 1) REMPI in the A(2)Σ(+) ← X(2)Π γ-bands around λ = 226 nm. A nonlinear desorption yield of neutral NO is observed with an exponent of m = 1.4 ± 0.2. At a fluence of about 4 mJ/cm(2) a desorption cross section of σ(1) = (1.1 ± 0.4) × 10(-17) cm(2) is observed, accompanied with a lower one of σ(2) = (2.6 ± 0.3) × 10(-19) cm(2) observable at higher total fluence. A nonthermal rovibrational population distribution is observed with an average rotational energy of <E(rot)> = 38.6 meV (311 cm(-1)), a vibrational energy of <E(vib)> = 136 meV (1097 cm(-1)) and an electronic energy of <E(el)> = 3.9 meV (31 cm(-1)).
authors: Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Wilhelm Klemm Strasse 10, 48149 Münster, Germany. b.siemer@uni-muenster.de
authors: Björn
authors: B
authors: Siemer
authors: Tim
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authors: Hoger
authors: Marco
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authors: Rutkowski
authors: Stefan
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authors: Düsterer
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