[molpro-user] complex expressions

[LUTZ J.]

Dear Molpro users,

I am trying to enter a complex expression as a geometrical parameter in my input for the CH3F system. It is well known that the angles of a C3V symmetric top are related by cos(b) = 1 - 3/2 sin^2(a), where in this case b is the HCH angle and a is the FCH angle. 
My z-matrix is as follows:

----------------------------------------------------------------

 ***,
memory,100,m
angstrom

geometry={
c1,
h1,  c1,  rch;
f1,  c1,  rcf,  h1, acf;
h2,  c1,  rch,  h1, acos(1-1.5*(sin(acf))^2), f1, 120.000;
h3,  c1,  rch,  h1, acos(1-1.5*(sin(acf))^2), f1, 240.000}

rch = 1.087
!!!!    ach = 110.2   -->   acos(1-1.5*(sin(108.73))^2) evaluates to 110.20
rcf = 1.383
acf = 108.73

rhf

----------------------------------------------------------------

Molpro outputs the following 

----------------------------------------------------------------
  ***,
 memory,100,m
 angstrom

 geometry={
 c1,
 h1,  c1,  rch;
 f1,  c1,  rcf,  h1, acf;
 h2,  c1,  rch,  h1, acos(1-1.5*(sin(acf))^2), f1, 120.000;
 h3,  c1,  rch,  h1, acos(1-1.5*(sin(acf))^2), f1, 240.000}

 rch = 1.087
                                                        !!!!    ach = 110.2    ZUNIT=ANG

 SETTING RCH            =         1.08700000
 SETTING RCF            =         1.38300000
 SETTING ACF            =       108.73000000

 Variable memory set to  100000000 words,  buffer space   230000 words



 Recomputing integrals since basis changed


 Using spherical harmonics

 ? Possible error in Z matrix
 Line                        4  connection                        2  expr=
 ACOS(1-1.5*(SIN(ACF))^2)
 ? Apparently depends on a variable, but not one that is yet defined

 Z matrix     Current Z-matrix
 ========
 
 Records:   700.0   700.0
 Maximum, total, and current numbers of geometry points 100   0   0
 Orientation using atomic masses  
 Rotational constants:       0.0000000      0.0000000      0.0000000 GHz  (calculated with average atomic masses)
 Unique atoms/degeneracy:

   #     Tag     N1 Distance  N2 Angle     N3 Angle        J
   Grp   Chg     Distance     Angle        Angle                  x            y            z

   1  1   C1    
      1  6.0    0.0000000    0.0000000    0.0000000              0.0000000    0.0000000    0.0000000
   2  2   H1      1 RCH      
      2  1.0    1.0870000    0.0000000    0.0000000              0.0000000    0.0000000    0.0000000
   3  3   F1      1 RCF        2 ACF      
      3  9.0    1.3830000  108.7300000    0.0000000              0.0000000    0.0000000    0.0000000
   4  4   H2      1 RCH        2 ACOS(1-1   3 120.000      0
      2  1.0    1.0870000  110.2021617  120.0000000              0.0000000    0.0000000    0.0000000
   5  5   H3      1 RCH        2 ACOS(1-1   3 240.000      0
      2  1.0    1.0870000  110.2021617  240.0000000              0.0000000    0.0000000    0.0000000
 
 Variables on which Z-matrix depends:
 Name:                RCH             RCF             ACF             RCH                                             RCF             ACF 
 Value:         0.0000000 A     0.0000000 A     0.0000000 D     0.0000000 A     0.0000000       0.0000000       0.0000000 A     0.0000000 D
 Name:                ACF             RCH                                             RCH                                
 Value:         0.0000000 D     0.0000000 A     0.0000000       0.0000000       0.0000000 A     0.0000000       0.0000000
 ? Error 
 ? Error in Z matrix
 ? The problem occurs in zmatrix.f:zmat_evaluate
 
 ERROR EXIT
 CURRENT STACK:      MAIN

----------------------------------------------------------------------------------------

When I run the job I get four command line errors:

ERROR in 'sin(expr)' operand type mismatch
ERROR in 'sin(expr)' operand type mismatch
ERROR in 'sin(expr)' operand type mismatch
ERROR in 'sin(expr)' operand type mismatch

However, it can be read from the z-matrix output above (the output, not the echo of the input) that Molpro evaluates the complex expression correctly. It seems to complain about the complex expression entry, but then evaluates it correctly!  I have no idea what could be the source of the error causing the program to abort.

Can anyone offer a suggestion so I can proceed?
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