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1.
It has been claimed that so-called abnormal infrared effects (AIREs) occur in the infrared reflectance spectra of particulate metals deposited on both moderately reflecting (e.g. glassy carbon) and highly reflecting (e.g. smooth Pt) substrates upon chemisorption on the metal particles of IR-absorbing molecules, typically CO. These AIREs would be characterized by: (i) increase, instead of decrease, of the IR reflectance at the absorption frequency of the chemisorbed molecule, producing anti-absorption bands (band inversion) (ii) enhancement of the intensity of the IR bands of the chemisorbed molecule (iii) increase of the full width at half-maximum (FWHM) of the absorption band of the chemisorbed molecule. It is proved here that these results need not be assigned to any new abnormal effects, but, on the contrary, are well-known phenomena. (i) Band inversion is perfectly explained by Fresnel's reflectance equations. (ii) The intensity increase of the IR bands is due to SEIRA (surface enhanced infrared absorption), a phenomenon discovered in 1980, and due to the large electric field increase produced between metal particles dispersed in a matrix. (iii) The somewhat higher FWHM of CO adsorbed on particulate as compared with massive metals can well be accounted for by the sensitivity of this parameter to changes in adsorbent structure. In conclusion, no new abnormal effects have to be invoked in order to explain the reported behaviour of CO and other molecules adsorbed on particulate metals deposited on moderately reflecting substrates, a category which also includes highly reflecting metals covered by a suitable layer of metal particles.  相似文献   

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《Orthodontic Waves》2011,70(4):158-160
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《Orthodontic Waves》2013,72(4):166-168
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《Orthodontic Waves》2014,73(4):148-150
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《Orthodontic Waves》2009,68(4):195-196
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《Orthodontic Waves》2012,71(4):140-142
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《上海口腔医学》2005,14(6):673-676
AA.Hardianto2005,14(2):117Arild Stenvik2005,14(3):238艾红军2005,14(4):3872005,14(6):617B毕玮2005,14(2):120边华琴2005,14(1):24卞继峰2005,14(5):479C蔡以理2005,14(5):495蔡中2005,14(3):301曹惠菊2005,14(2):1902005,14(3):243曹谊林2005,14(3):260曹寅2005,14(3):273常新2005,14(4):387巢永烈2005,14(4):392陈爱国2005,14(1):37陈安威2005,14(2):123陈传俊2005,14(5):519陈岱韵2005,14(5):452陈发明2005,14(5):485陈关福2005,14(6):664陈光全2005,14(5):549陈罕2005,14(1):2陈吉华2005,14(4):397陈杰2005,14(6):645陈炯2005,1…  相似文献   

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