diff --git a/code/termspecs/termspec.pdf-sampling-ic1-ddxc b/code/termspecs/termspec.pdf-sampling-ic1-ddxc
new file mode 100644
index 0000000..f65e398
--- /dev/null
+++ b/code/termspecs/termspec.pdf-sampling-ic1-ddxc
@@ -0,0 +1,14 @@
+# collect samples for pdf estimation from ic1 case
+# sampling region (xs, xe) hard-coded for ic1 case
+
+[u, v, w, y]
+
+# field_name (arg_name=arg (, pair)* ) = expression
+
+c = 1.0 - y
+
+ddxc (export=true, xs=176, xe=400) = ddx(c)
+
+fsd (export=true, xs=176, xe=400) = sqrt (sqr(ddx(c)) + sqr(ddy(c)) + sqr(ddz(c)))
+
+avg { c, fsd, ddxc }