Size dependence of the photophoretic force

S. Arnold, M. Lewittes

Research output: Contribution to journalArticlepeer-review


The photophoretic force on a micron-sized sphere of glycerol is measured for a continuously changing size parameter (through evaporation) for excitation at 10.63 and 9.58 μ. Although the force at 9.58 μ is always forward ("positive" photophoresis), the force at 10.63 μ reverses in sign ("negative" photophoresis) and shows a periodic structure in size parameter (2πR/λ) with a periodicity of 0.77±0.03. It is shown that the point of reversal may be used in obtaining the imaginary component of the refractive index. The possibility of solar levitation of atmospheric aerosols is discussed.

Original languageEnglish (US)
Pages (from-to)5314-5319
Number of pages6
JournalJournal of Applied Physics
Issue number7
StatePublished - 1982

ASJC Scopus subject areas

  • General Physics and Astronomy


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