Chimie Théorique » Opt'n Path

subroutine egrad_gaussian(e,geomcart,gradcart)

  ! This routines calculates the energy and the gradient of 

  ! a molecule, using Gaussian 

  use Path_module, only : Nat, renum,Order,OrderInv,AtName, Coord, dzdc, indzmat,Nom,Atome, massat, unit,ProgExe

  use Io_module

  IMPLICIT NONE

  ! Energy (calculated if F300K=.F., else estimated)

  REAL(KREAL), INTENT (OUT) :: e

  ! Nb degree of freedom

  REAL(KREAL), INTENT (IN) :: geomcart(Nat,3)

  ! Gradient calculated at Geom geometry

  REAL(KREAL), INTENT (OUT) :: gradcart(3*NAt)

  ! ======================================================================

  character(LCHARS) :: LINE

  logical           :: debug, G03Ok

  LOGICAL, SAVE :: first=.true.

  REAL(KREAL) :: Pi

  INTEGER(KINT) :: ItG03

  INTEGER(KINT) :: iat, i, n3at

  INTEGER(KINT) :: ITmp1, ITmp2

  CHARACTER(132) :: FileIn, FileOut, FileChk

  CHARACTER(3) :: SepIn=' < ', SepOut=' > '

  CHARACTER(VLCHARS), SAVE :: RunCommand

!  LOGICAL, SAVE :: FCopyRstrt=.False., FOrderChecked=.False.

  ! ======================================================================

  LOGICAL, EXTERNAL :: valid

  ! ======================================================================

  Pi=dacos(-1.0d0)

  n3at=3*nat

  debug=valid('EGRAD')

  if (debug) Call Header("Entering Egrad_gaussian")

  if (first) THEN

     First=.FALSE.

     call system("uname > Path.tmp")

     OPEN(IOTMP,FILE='Path.tmp')

     READ(IOTMP,'(A)') Line

     CLOSE(IOTMP)

     IF (index(Line,'CYGWIN').NE.0) THEN

        SepIn='   '

        SepOut='   '

     END IF

  END IF

  gradcart=0.

  E=0.

  FileIn=Trim(CalcName) // "." // Trim(ISuffix)

  FileOut=Trim(CalcName) // "." // Trim(OSuffix)

  FileChk=Trim(CalcName) // ".chk"

  RunCommand=Trim(ProgExe) // SepIn // Trim(FileIn) // SepOut // Trim(FileOut)

  IF (DEBUG) WRITE(*,*)'RunCommand:',TRIM(RunCommand)

  ! we create the input file

  OPEN(IOTMP,File=FileIn)

  Current => Gauss_root

  DO WHILE (ASSOCIATED(Current%next))

     WRITE(IOTMP,'(1X,A)') Trim(current%line)

     WRITE(*,'(1X,A)') Trim(current%line)

     Current => current%next

  END DO

  WRITE(IOTMP,*) 

  Current => Gauss_comment

  DO WHILE (ASSOCIATED(Current%next))

     WRITE(IOTMP,'(1X,A)') Trim(current%line)

     Current => current%next

  END DO

  !  WRITE(IOOUT,"('Geometry ',I3,'/',I3,' for iteration ',I3)"),Igeom,NgeomF,Iopt

  WRITE(IOTMP,*) 

  WRITE(IOTMP,*) Trim(Gauss_charge)

  DO I=1,Nat

     If (renum) THEN

        Iat=Order(I)

        WRITE(IOTMP,'(1X,A10,3(1X,F15.8),A)') Trim(AtName(I)),GeomCart(Iat,:), TRIM(Gauss_Paste(I))

     ELSE

        Iat=OrderInv(I)

        WRITE(IOTMP,'(1X,A10,3(1X,F15.8),A)') Trim(AtName(Iat)),GeomCart(I,:), TRIM(Gauss_Paste(Iat))

     END IF

  END DO

  WRITE(IOTMP,*) 

  Current => Gauss_End

  DO WHILE (ASSOCIATED(Current%next))

     WRITE(IOTMP,'(1X,A)') Trim(current%line)

     Current => current%next

  END DO

  WRITE(IOTMP,*) 

  CLOSE(IOTMP)

  IF (debug) THEN

     WRITE(*,*) 'DBG EGRAD ' //  Trim(FileIn),' COORD=',TRIM(COORD)

     call system('cat ' // Trim(FileIn))

  END IF

!!! PFL 15th March 2008 ->

! Sometimes for unknown reasons G03 fails.

! We thus add one test to check that Gaussian has finisehd properly.

! We also check that we do not run an infinite loop...

 G03Ok=.FALSE.

 ItG03=0

  DO WHILE ((.NOT.G03Ok).AND.(ItG03<3))

   ItG03=ItG03+1

  call system(RunCommand)

 OPEN(IOTMP,FILE=FileOut, STATUS='old', POSITION='APPEND')

 BACKSPACE(IOTMP)

 READ(IOTMP,'(A)') Line

 IF (LINE(2:19).EQ.'Normal termination')  G03Ok=.TRUE.

  END DO

  CLOSE(IOTMP)

  IF (.NOT.G03Ok) THEN

     WRITE(*,*) "Egrad_gaussian Failed..."

     WRITE(*,*) "Wrong termination of Gaussian after 3 tries. Check Input and geometry"

     STOP

  END IF

  if (debug) WRITE(*,*) 'DBG EGRAD, back from calculation'

  ! Whatever the coordinate system, we read the cartesian gradient

  ! and we convert it to Zmat or other if needed

  OPEN(IOTMP,FILE=FileOut, STATUS='old')

  ! We first search for the forces

  READ(IOTMP,'(A)') LINE

  DO WHILE (INDEX(LINE,'Forces (Hartrees/Bohr)')==0)

     ! here, we have a problem, because there are so many ways to write E for Gaussian :-)

     ! but we do not really need E except if we want to weight the different points

     ! on the path... that will be done later :-)

     ! And I should use ConvGaussXmol ...

! PFL 3rd Jan 2008 ->

! I have finally upgraded the energy reading phase so that it should be able to read 

! many formats corresponding to HF, DFT, MP2, AM1, PM3, ONIOM with or w/o PCM

! For MP2, energy is after the last =

     IF ((Line(2:9)=="E2 =    ")) THEN

      Itmp1=Index(LINE,"=",BACK=.TRUE.)+1

    READ(LINE(Itmp1:),*) e

      END IF

! For other methods, it is after the first =

     IF ((LINE(2:9)=='Energy= ').OR.(Line(2:9)=="SCF Done").OR.(Line(2:9)=="ONIOM: e") &

   .OR.(Line(2:9)==" with al") &

         .OR.(Line(2:31)=="Counterpoise: corrected energy")) THEN

      Itmp1=Index(LINE,"=")+1

    READ(LINE(Itmp1:),*) e

  END IF

! <- PFL 3 Jan 2008

     READ(IOTMP,'(A)') LINE

  END DO

  if (debug) WRITE(*,*) "GradCart reading - renum=",Renum

  READ(IOTMP,'(A)') LINE

  READ(IOTMP,'(A)') LINE

  DO I=1,Nat

     Iat=I

     IF (renum) Iat=Order(I)

     READ(IOTMP,*)  Itmp1,ITmp2, GradCart(3*Iat-2:3*Iat)

     if (debug) WRITE(*,*) "I,Iat,GradCart:",I,Iat,GradCart(3*Iat-2:3*Iat)

  END DO

! Gaussian gives the Forces in ua/a0, so we convert it into the 

! gradient in ua/Angstrom 

  gradCart=-1.0d0*gradCart*Unit

!  if (debug.AND.(COORD.EQ.'ZMAT')) THEN

!     DO WHILE (INDEX(LINE,'Internal Coordinate Forces')==0)

!        READ(IOTMP,'(A)') LINE

!!        WRITE(*,*) 'Pas bon:' // TRIM(LINE)

!     END DO

!     WRITE(*,*) TRIM(LINE)

!     DO I=1,Nat+2

!        READ(IOTMP,'(A)') LINE

!        WRITE(*,*) TRIM(LINE)

!     END DO

!  END IF

  CLOSE(IOTMP)

  if (debug) Call header("Egrad_gaussian Over")

  RETURN

!999 CONTINUE

!  if (.NOT.Ftmp) WRITE(*,*) 'We should not be here !!!!'

!  STOP

  ! ======================================================================

end subroutine egrad_gaussian