Helmholtz Differential Equation--Parabolic Cylindrical Coordinates
In parabolic cylindrical coordinates, the scale factors are
,
and the separation functions are
, giving Stäckel determinant of
. the Helmholtz differential equation is
 |
(1)
|
attempt separation of variables by writing
 |
(2)
|
then the Helmholtz differential equation becomes
 |
(3)
|
Divide by
,
 |
(4)
|
Separating the
part,
 |
(5)
|
 |
(6)
|
 |
(7)
|
so
 |
(8)
|
which has solution
 |
(9)
|
and
 |
(10)
|
This can be separated
so
 |
(13)
|
 |
(14)
|
These are the Weber differential equations, and the solutions are known as Parabolic Cylinder Functions.
REFERENCES:
Moon, P. and Spencer, D. E. Field Theory Handbook, Including Coordinate Systems, Differential Equations, and Their Solutions, 2nd ed. New York: Springer-Verlag, p. 36, 1988.
Morse, P. M. and Feshbach, H. Methods of Theoretical Physics, Part I. New York: McGraw-Hill, pp. 515 and 658, 1953.