$HESS group
            (relevant for RUNTYP=HESSIAN if RDHESS=.TRUE.)
         (relevant for RUNTYP=IRC if FREQ,CMODE not given)
      (relevant for RUNTYP=OPTIMIZE,SADPOINT if HESS=READ)
 
    Formatted force constant matrix (FCM), i.e. hessian
matrix.  This data is punched out by a RUNTYP=HESSIAN job,
in the correct format for subsequent runs.  The first card
in the group must be a title card.
 
    $HESS information is always punched in Cartesians.  It
will be transformed into internal coordinate space if a
geometry search uses internals.  It will be mass weighted
(according to $MASS) for IRC and frequency runs.
 
    The initial FCM is updated during the course of a
geometry optimization or saddle point search, and will be
punched if a run exhausts its time limit.  This allows
restarts where the job leaves off.  You may want to read
this FCM back into the program for your restart, or you
may prefer to regenerate a new initial hessian.  In any
case, this updated hessian is absolutely not suitable for
frequency prediction!
 
24 lines are written.
Edited by Shiro KOSEKI on Tue May 17 15:19:38 2022.