Page 51 - Mike's published articles
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andgrenpigments,however,showdistinctivefeaturesintheinfraredregion(Fig.5).InFigs.6and7, thesolidphasespectrashownarecalculatedfrom10%lesthepercentageofreflectedlight,scatered lightandlighttransmitedbythesample.Thisissimplyforthepurposeofaproximatecomparisonwith theliquidphasespectrawhichareintheabsorbancemode.Giventhehighextinctioncoeficientexpected forsuchpigments,itismostlikelythattheobservedtransmitedlightistransmitedindirectlybyaseries ofreflectionsfromparticlefacetsinthethicknesoftheratheropenfilm.
R
A
JR
50 750 10 1250 150 480
Frequency/cm1 FrequencyIcm1
2080
Fig.2.Redpigment,solidline=(1-solidphasereflect- Fig.3.Bluepigment,solidline=(1-solidphase ance)spectrum,dotedline=liquidphase"absorbance"reflectance)spectrum,dotedline=liquidphase spectrum,(bothinarbitraryunits). "absorbance"spectrum,bothinarbitraryunits.
Frequency/cm
-1
20
FrecjencyIcm Fig.4.Reflectancespectraof(1)=lightredpigment, Fig.5.Reflectancespectrumofbluepig-
(2)=RedPigment,(3)=yelowpigment,alinarbi- mentinarbitraryunits. tralyunits.
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