In this paper we report the results of a Compton profile study on poly
crystalline platinum. The measurement has been made using Am-241 gamma
-rays and is compared with APW calculations of Papanicolaou et al, and
also with our calculations based on the renormalized-free-atom (RFA)
model. It is seen that tile incorporation of electron correlation effe
cts improves slightly the agreement bettween APW theory and experiment
but the best fit to our experimental data is seen for the simple RFA
model for 5d(9.2)6s(0.8) configuration. A comparison of the equal vale
nce-electron-density Compton profiles of platinum and the other two is
ogroup metals, namely palladium and nickel, reveals an interesting tre
nd for the d-band width in agreement with the results based on photoem
ission measurements. The d-band occupancy as determined from RFA analy
sis is in agreement with Lytle's estimates.