{'fraction_non_alphanumeric': 0.058771929824561406, 'fraction_numerical': 0.03245614035087719, 'mean_word_length': 5.595375722543353, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 1, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Photochemistry of adsorbed molecules. XVII. Photodissociation at 193 nm of CH3Br adsorbed on LiF(001) and NaCl(001)

The adsorption and photodissociation of CH3Br(ad) on LiF(001) and NaCl(001) have been studied by temperature programed desorption (TPD) and angle-resolved time-of-flight mass spectrometry. The results of TPD on LiF(001) indicated that CH3Br(ad) formed a first adsorbed layer in which repulsive adsorbate–adsorbate interactions dominated. At high coverages, the TPD profiles on LiF(001) were characteristic of multilayer (“zero-order”) desorption but at no time were separate monolayer and multilayer TPD peaks observed. In contrast, on NaCl(001) CH3Br(ad) formed a distinct monolayer phase before growth of the second and subsequent layers. Methyl radicals were produced by photodissociation of CH3Br(ad) at 193 nm on both surfaces at coverages from submonolayer to >10 monolayers. The CH3(g) translational energy distribution, P(ET′), exhibited two coverage-dependent photodissociation channels; the first, termed the “direct” (DIR) channel, observed at multilayer coverages, had a P(ET′) centered at 2.4 eV, and the se...