Intensity dependence  Ar  400 nm
threshold
Channel closing:
 6 ħω
Ar:   Ip = 15.76 eV
1.7 x 1014 W/cm2: Up= 2.55 eV
Ip
 6 ħω
intensity
Text Box: 0 0.3 0.6
1.7 x 1014 W/cm2
3.2 x 1014 W/cm2
-0.8        0.4       0         0.4       0.8
3.9 x 1014 W/cm2
P|| (a.u.)
-0.8      -0.4        0         0.4       0.8