$RAMAN group               (relevant for all SCFTYPs)                           
    This input controls the computation of Raman intensity                      
by the numerical differentiation produre of Komornicki and                      
others.  It is applicable to any wavefunction for which                         
the analytic gradient is available, including some MP2 and                      
CI cases.  The calculation involves the computation of 19                       
nuclear gradients, one without applied electric fields,                         
plus 18 no symmetry runs with electric fields applied in                        
various directions.  The numerical second differencing                          
produces intensity values with 2-3 digits of accuracy.                          
    This run must follow an earlier RUNTYP=HESSIAN job,                         
and the $GRAD and $HESS inputs from that first job must be                      
given as input.  If the $DIPDR is computed analytically                         
by this Hessian job, it too may be read in, if not, the                         
numerical Raman job will evaluate $DIPDR.  Once the data                        
from the 19 applied fields is available, the $ALPDR tensor                      
is evaluated.  Then the nuclear derivatives of the dipole                       
moment and alpha polarizability will be combined with the                       
normal coordinate information to produce the IR and Raman                       
intensity of each mode.                                                         
    To study isotopic substitution speedily, provide $GRAD,                     
$HESS, $DIPDR, and $ALPDR inputs, along with the desired                        
atomic masses in $MASS.                                                         
   The code does not permit semi-empirical or solvation                         
models to be used.                                                              
EFIELD = applied electric field strength.  The literature                       
         suggests values in the range 0.001 to 0.005.                           
         (default = 0.002 a.u.)                                                 

generated on 7/7/2017