Abstract
Results of a spreading pressure study of the commensurate solid to domain-wall fluid (CS-DWF) transition of monolayer He4 on graphite are reported. The CS-DWF phase boundary between 1.2 and 2.8 K is determined from the location of pronounced maxima in isothermal compressibility data constructed from the spreading pressure data. The scaling of the compressibility data at this transition is consistent with a chiral crossover exponent smaller than (2/3.