Slip correction measurements for aerosol particles of doublet and triangular triplet aggregates of spheres

Slip correction measurements were made on six doublets and six triangular triplet aggregates of uniform plastic spheres in an improved Millikan apparatus. The results were compared with theoretical methods for correcting aggregates of uniform spheres for slip. Each calculated value of the slip correction factor, C(D/sub s/), was used to solve for the adjusted sphere factor (psi) in the Knudsen-Weber form of the slip correction equation where D/sub s/ = psiD1 and D1 is the sphere diameter. For doublets (n/sub p/ = 2) of 1.18-μm polystyrene latex spheres in parallel motion, the average value of psi was computed to be 1.384. For triangular triplets (n/sub p/ = 3) in parallel motion, the average value of psi was computed to be 1.453. Values of psi that were computed from the reported measurements of other investigators showed fair agreement with our results