Cartesian contour maps

Fig. 15. Cartesian contour maps of ArD from reaction Ar + D2 at medium and low energies (CM energies indicated).

Cartesian contour maps represent the velocity-space distribution, dV(0, m/)/ du, where du = (u f du d co. Cartesian maps are invariant under a transformation to the laboratory system of coordinates... 

Comparison of Alignment Charts and Cartesian Graphs. There are typically fewer lines on an alignment chart as compared to Cartesian plots. This reduces error introduced by interpolation and inconsistency between scales. For example, to find a point (x,j) on a Cartesian graph one draws two lines, one perpendicular to each axis, and these reference lines intersect at the point x,j). This point (x,j) may correspond to some finite value found by rea ding a contour map represented by a family of curves corresponding to different values of the function. 

An alignment chart is used by drawing one reference line through the two axes. This reference line, which need not be perpendicular to either axis, crosses a result axis at a unique finite value. This result axis represents the contour map on a Cartesian graph. Thus each line on an alignment chart represents a point on a Cartesian graph. 

Figure 3. Upper panel DF angular distributions at 0.80 kcal/mol and 1.68 kcal/tnol collision energy. Lower panel Cartesian flux contour maps generated from these data.

---