Vector |
g(m2) = ( l1 l2 l3 ) ( m1 m2 -m1-m2 )
public static void ThreeJSymbolM( double l1, double l2, double l3, double m1, out double m2min, out double m2max, double[] thrcof, int ndim, out int errflag )
errflag=0 No errors.
errflag=1 Either l1 < abs(m1) or l1+abs(m1) non-integer.
errflag=2 abs(l1-l2)<= l3 <= l1+l2 not satisfied.
errflag=3 l1+l2+l3 not an integer.
errflag=4 m2max-m2min not an integer.
errflag=5 m2max less than m2min.
errflag=6 ndim less than m2max-m2min+1.
Description: ------------ Although conventionally the parameters of the vector addition coefficients satisfy certain restrictions, such as being integers or integers plus 1/2, the restrictions imposed on input to this subroutine are somewhat weaker. See, for example, Section 27.9 of Abramowitz and Stegun or Appendix C of Volume II of A. Messiah. The restrictions imposed by this subroutine are 1. l1 >= abs(m1) and l1+abs(m1) must be an integer 2. abs(l1-l2) <= l3 <= l1+l2 3. l1+l2+l3 must be an integer 4. m2max-m2min must be an integer, where m2max=min(l2,l3-m1) and m2min=max(-l2,-l3-m1) If the conventional restrictions are satisfied, then these restrictions are also met. The user should be cautious in using input parameters that do not satisfy the conventional restrictions. For example, the the subroutine produces values of g(m2) = (0.75 1.50 1.75 ) (0.25 m2 -0.25-m2) for m2=-1.5,-0.5,0.5,1.5 but none of the symmetry properties of the 3j symbol, set forth on page 1056 of Messiah, is satisfied. The subroutine generates g(m2min), g(m2min+1), ..., g(m2max) where m2min and m2max are defined above. The sequence g(m2) is generated by a three-term recurrence algorithm with scaling to control overflow. Both backward and forward recurrence are used to maintain numerical stability. The two recurrence sequences are matched at an interior point and are normalized from the unitary property of 3j coefficients and Wigner's phase convention. The algorithm is suited to applications in which large quantum numbers arise, such as in molecular dynamics. References: ----------- 1. Abramowitz, M., and Stegun, I. A., Eds., Handbook of Mathematical Functions with Formulas, Graphs and Mathematical Tables, NBS Applied Mathematics Series 55, June 1964 and subsequent printings. 2. Messiah, Albert., Quantum Mechanics, Volume II, North-Holland Publishing Company, 1963. 3. Schulten, Klaus and Gordon, Roy G., Exact recursive evaluation of 3j and 6j coefficients for quantum- mechanical coupling of angular momenta, J Math Phys, v 16, no. 10, October 1975, pp. 1961-1970. 4. Schulten, Klaus and Gordon, Roy G., Semiclassical approximations to 3j and 6j coefficients for quantum-mechanical coupling of angular momenta, J Math Phys, v 16, no. 10, October 1975, pp. 1971-1988. 5. Schulten, Klaus and Gordon, Roy G., Recursive evaluation of 3j and 6j coefficients, Computer Phys Comm, v 11, 1976, pp. 269-278. 6. SLATEC library, category C19, double precision algorithm DRC3JM.F Keywords: 3j coefficients, 3j symbols, Clebsch-Gordan coefficients, Racah coefficients, vector addition coefficients, Wigner coefficients Author: Gordon, R. G., Harvard University Schulten, K., Max Planck Institute Revision history (YYMMDD) 750101 DATE WRITTEN 880515 SLATEC prologue added by G. C. Nielson, NBS; parameters HUGE and TINY revised to depend on D1MACH. 891229 Prologue description rewritten; other prologue sections revised; MMATCH (location of match point for recurrences) removed from argument list; argument IER changed to serve only as an error flag (previously, in cases without error, it returned the number of scalings); number of error codes increased to provide more precise error information; program comments revised; SLATEC error handler calls introduced to enable printing of error messages to meet SLATEC standards. These changes were done by D. W. Lozier, M. A. McClain and J. M. Smith of the National Institute of Standards and Technology, formerly NBS. 910415 Mixed type expressions eliminated; variable C1 initialized; description of THRCOF expanded. These changes were done by D. W. Lozier. 7. Rewritting of the SLATEX algorithm in C++ and adaption to the Matpack C++ Numerics and Graphics Library by Berndt M. Gammel in June 1997.