Installing NBO 5.G in GAMESS (version 24-MAR-2007 R1):

1.  Compile and link GAMESS.  Ensure that GAMESS functions
    appropriately before attempting the NBO 5.G installation.

2.  Use the Enable program distributed with NBO 5.G to prepare
    gmsnbo.src.  Move this file to the source directory of the
    GAMESS distribution.

3.  In the GAMESS source directory, make the following modifications
    to the source files prppop.src, rhfuhf.src, and iolib.src:

    a)  prppop.src:  Uncomment the call to RUNNBO.  Also, modify
        this call to read the following:

           IF(NPROC.EQ.1) CALL RUNNBO

        Note that NBO is not prepared to function correctly in
        the parallel version of GAMESS.  Sequential runs only!

    b)  rhfuhf.src:  Insert the COMMON block /ENEDA/ in the RHFCL
        and UHFOP routines.

           COMMON /ENEDA / E0

    c)  rhfuhf.src:  Insert the following instruction immediately
        after the ETOT = EHF+EN line of the UHFOP routine.

           IF(ITER.EQ.1) E0 = ETOT

    d)  iolib.src:  In the routine DAREAD, change the following
        instruction

           IF(LEN.LE.0           ) GO TO 810

        to read

           IF(LEN.LT.0           ) GO TO 810

        Also, change the instruction

           CALL DARD(V(IS),LENW,IDAF,NSP,IDTYP)

        to read 

           IF(LENW .GT. 0) CALL DARD(V(IS),LENW,IDAF,NSP,IDTYP)

    e)  iolib.src:  In the routine DAWRIT, change the following
        instruction

           IF (N .GT. 0 .AND. LEN .NE. IFILEN(NREC)) GO TO 800

        to read

           IF (N .GT. 0 .AND. LEN .GT. IFILEN(NREC)) GO TO 800

4.  Add the following line to the activate and compile steps of the
    compall script of the root GAMESS directory.

           ./comp gmsnbo

5.  Make the following changes to the comp script:

    a:  If you're using f2c/gcc compilation on a Linux machine, 
        include the -Nx800 compiler (f2c) option.

6.  Include gmsnbo.o in the link-edit step of the lked script.

7.  Compile and link GAMESS.


NBO Limitations:

1.  NBO will fail if GAMESS is run in parallel.  Run NBO only for 
    single-node (sequential) calculations.