Experimental versus Theoretical Data for PEG, PPG, and PTMEG
Plot of cross-section at 300 K vs. oligomer size
for PEGn, PPGn, and PTMEGn cationized by Na+.
Experimental and theoretical cross-sections agree
within 1-2% for all oligomers.
Plots of cross-section vs. temperature for the PPG 5-mer and 14-mer and PTMEG 5-mer
and 11-mer cationized by Na+. The increase in cross-section at low temperature is due to the
nature of the ion-He interaction potential. From 400 to 600 K, the cross-section of Na+PPG5
slightly decreases while the cross-section for Na+PTMEG5 remains somewhat constant. In this
same temperature range, the cross-sections of Na+PPG14 and Na+PTMEG11 dramatically
increase. This increase in cross-section at higher temperature is due to the unraveling of part of
the oligomer that is not coordinated to the Na+ ion.