$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! ========================================================== $GRAD group (relevant for RUNTYP=OPTIMIZE or SADPOINT) (relevant for RUNTYP=HESSIAN when RDHESS=.TRUE.) Formatted gradient vector at the $DATA geometry. This data is read in the same format it was punched out. For RUNTYP=HESSIAN, this information is used to determine if you are at a stationary point, and possibly for projection. If omitted, the program pretends the gradient is zero, and otherwise proceeds normally. For geometry searches, this information (if known) can be read into the program so that the first step can be taken instantly. ==========================================================

generated on 7/7/2017