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    Names: »cpc11«

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└─⟦621cfb9a2⟧ Bits:30002817 RC8000 Dump tape fra HCØ.  Detaljer om "HC8000" projekt.
    └─⟦0364f57e3⟧ 
        └─⟦this⟧ »cpc11« 

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c   ACYA MCHF77.  A GENERAL MULTI-CONFIGURATION HARTREE-FOCK PROGRAM.
c   C.F. FISCHER.
c   REF. IN COMP. PHYS. COMMUN. 14 (1978) 145
C     ------------------------------------------------------------------
C                    M C H F 7 7
C     ------------------------------------------------------------------
C
C         A MULTI-CONFIGURATION HARTREE FOCK PROGRAM FOR ATOMS FOR THE
C     IBM SYSTEM 360/370 (DOUBLE PRECISION) BY
C
C                    CHARLOTTE FROESE FISCHER
C                    DEPARTMENT OF COMPUTER SCIENCE
C                    PENN STATE UNIVERSITY
C                    UNIVERSITY PARK, PA 16801
C
C
C     REVISION OF  : MCHF72
C                    COMPUTER PHYSICS COMMUNICATIONS 4 (1972) 107
C      DEVELOPED AT: THE UNIVERSITY OF WATERLOO
C                    WATERLOO, ONTARIO
C      SUPPORTED BY: THE NATIONAL RESEARCH COUNCIL OF CANADA
C
C
C     REVISION OF  : MULTI-CONFIGURATION HARTREE-FOCK
C                    COMPUTER PHYSICS COMMUNICATIONS 1 (1969) 151
C      DEVELOPED AT: THE UNIVERSITY OF BRITISH COLUMBIA
C                    VANCOUVER, BC
C      SUPPORTED BY: THE NATIONAL RESEARCH COUNCIL OF CANADA
C
C
C
C
C
C
C     THE PRESENT PROGRAM WAS DEVELOPED IN PART WHILE AT THE UNIVERSITY
C     OF WATERLOO AND SUPPORTED BY A NATIONAL RESEARCH COUNCIL OF
C     CANADA GRANT, AND IN PART AT PENN STATE SUPPORTED BY A US ERDA
C     GRANT.
C
C     ------------------------------------------------------------------
C     1        I N T R O D U C T I O N
C     ------------------------------------------------------------------
C
C     A MULTI-CONFIGURATION HARTREE-FOCK APPROXIMATION IS A WAVEFUNCTION
C     OF THE FORM
C
C        W(CLS) = SUM ON I     $ WT(I) * ! CONFIG(I) > $
C                (I .LE. NCFG)
C
C     WHERE CLS SPECIFIES THE STATE AND  !   > DESIGNATES A
C     A CONFIGURATION STATE FUNCTION DEFINED IN TERMS OF SPIN-ORBITALS
C     OF THE FORM
C
C        PHI =  (1/R)P(NL;R)<SPHERICAL HARMONIC><SPIN FUNCTION>
C
C     BOTH THE COEFFICIENTS WT(I) IN THE EXPANSION AND THE RADIAL
C     FUNCTIONS P(NL;R) ARE DETERMINED VARIATIONALLY SO AS TO LEAVE
C     THE TOTAL ENERGY OF THE SYSTEM STATIONARY WITH RESPECT TO ALL
C     PERTURBATIONS SATISFYING CERTAIN ORTHOGONALITY CONSTRAINTS.  ALL
C     ORBITALS WITHIN  A CONFIGURATION STATE FUNCTION ARE ASSUMED TO BE
C     ORTHOGONAL BUT SOME FLEXIBILITY IS ALLOWED IN THE ORTHOGONALITY
C     CONSTRAINT OF ORBITALS  IN DIFFERENT CONFIGURATIONS.   THE
C     CONSTRAINTS MUST BE SUCH THAT THE MOST GENERAL FORM OF THE ENERGY
C     EXPRESSION IS
C
C      E(ALS) = SUM ON I     $ WT(I)**2 * EAV(I) $
C              (I .LE. NCFG)
C
C             + SUM ON M   $A(M)*WT(J1(M))*WT(J2(M))*FK(M)(I1(M),I2(M))$
C              (M .LE. NF)
C
C             + SUM ON M   $B(M)*WT(J1(M))*WT(J2(M))*GK(M)(I1(M),I2(M))$
C              (M .LE. NG)
C
C             + SUM ON M   $D(M)*WT(J1(M))*WT(J2(M))
C              (M .LE. NR)
C                           *RK(M)(I1(M),I2(M),I3(M),I4(M))
C
C                           *<IO(M)!JO(M)>**P(M)
C
C             + SUM ON M   $C(M)*WT(J1(M))*WT(J2(M))
C              (M .LE. NL)
C                           *L(I1(M),I2(M))*<IO(M)!JO(M)>**P(M)
C
C     WHERE EAV(I) IS THE AVERAGE ENERGY FOR THE I'TH CONFIGURATION,
C     FK(I,J), GK(I,J) AND RK(I1, I2, I3, I4) ARE SLATER INTEGRALS AND
C     THE CONTRIBUTION FROM THE ONE-ELECTRON PART OF THE HAMILTONIAN IS
C
C          I(NL,N'L) = -(1/2)L(NL,N'L)
C
C
C     NOTE THAT CONTRIBUTIONS FROM INTERACTIONS BETWEEN CONFIGURATIONS
C     CONTRIBUTE TWICE TO THE ENERGY EXPRESSION AND SO HAVE A FACTOR OF
C     TWO INCLUDED IN THE COEFFICIENT.  ALSO, BY THE SYMMETRY PROPERTIES
C     OF THE RK INTEGRALS, CERTAIN INTERACTION INTEGRALS MAY BE EXPRES-
C     SED AS FK OR GK INTEGRALS.  THE LATTER ARE TREATED MORE EFFIC-
C     IENTLY BY THE PROGRAM AND ARE THE PREFERRED FORM.
C
C     THE ABOVE EXPRESSION FOR THE ENERGY ASSUMES THE CONFIGURATION
C     STATE FUNCTIONS AND THE RADIAL FUNCTIONS HAVE EACH BEEN ORDERED
C     SO THAT THEY CAN BE REFERENCED BY THEIR INDEX IN THE LIST.  THE
C     INDICES FOR WT ALWAYS REFER TO CONFIGURATIONS WHEREAS THE
C     INDICES FOR THE  SLATER INTEGRALS, L AND OVERLAP INTEGRALS ARE
C     ALWAYS RADIAL FUNCTIONS.
C
C     THE STATIONARY CONDITIONS FOR THE RADIAL FUNCTIONS LEAD TO A
C     SYSTEM OF COUPLED INTEGRODIFFERENTIAL EQUATIONS THAT DEPEND ON THE
C     MIXING COEFFICIENTS WT(I).   THESE ARE THE MCHF EQUATIONS FOR THE
C     RADIAL FUNCTIONS.  AS IN A CONFIGURATION INTERACTION CALCULATION,
C     THE STATIONARY CONDITIONS FOR THE MIXING COEFFICIENTS ARE SOLU-
C     TIONS OF A SECULAR PROBLEM, (H - E)WT = 0, WHERE H IS THE INTER-
C     ACTION MATRIX, AND E THE TOTAL ENERGY.   CLEARLY THE ENTRIES IN
C     THE MATRIX DEPEND ON THE RADIAL FUNCTIONS.  CONSEQUENTLY THE
C     MCHF EQUATIONS  AND THE SECULAR PROBLEM ARE COUPLED .  TOGETHER
C     THEY DEFINE THE MCHF PROBLEM.   A MORE DETAILED DISCUSSION OF THE
C     DERIVATION OF HF EQUATIONS, THEIR PROPERTIES, AND THEIR NUMERICAL
C     SOLUTION IS CONTAINED IN THE BOOK, "THE HARTREE-FOCK METHOD FOR
C     ATOMS - A NUMERICAL APPROACH", PUBLISHED BY WILEY INTERSCIENCE,
C     NEW YORK, 1977.   SECTION AND EQUATION REFERENCES IN THE DOCUMENT-
C     ATION OF THIS PROGRAM REFER TO THIS BOOK.
C
C     THIS PROGRAM DETERMINES  THE RADIAL FUNCTIONS AS WELL AS THE
C     MIXING COEFFICIENTS FOR A MULTICONFIGURATION APPROXIMATION TO THE
C     TOTAL WAVEFUNCTION.
C
C     ------------------------------------------------------------------
C     2            I N P U T    D A T A
C     ------------------------------------------------------------------
C
C     THE PROGRAM ALLOWS DATA TO BE READ FROM, AND OUTPUT ROUTED TO,
C     A VARIETY OF UNITS.   UNLESS INDICATED OTHERWISE, THE INPUT DATA
C     HERE WILL BE DESCRIBED ASSUMING ALL DATA IS READ FROM THE SAME
C     UNIT, NAMELY INPUT UNIT 1.   IF SECTIONS ARE TO BE READ FROM OTHER
C     UNITS, THE DATA ON A GIVEN UNIT SHOULD APPEAR IN THE SAME ORDER.
C
CARD 0.  IUC, IUD, IUF, IUH, OUC, OUD, OUF, OUH IN FORMAT(4I3)
C
C     IUC - INPUT UNIT FOR THE CONFIGURATION CARDS (CARD 2.)
C     IUD - INPUT UNIT FOR THE DATA CARDS DEFINING THE ENERGY EXPRESSION
C           (CARDS 4., 5., 6., AND 7.) IF ANY.
C     IUF - INPUT UNIT FOR THE FUNCTION CARDS (CARD 8.) IF ANY.
C     IUH - INPUT UNIT FOR THE HAMILTONIAN MATRIX (CARD 10.) IF ANY.
C           THIS UNIT NUMBER SHOULD BE ZERO IF NO MATRIX IS TO BE READ.
C     OUC - OUTPUT UNIT FOR A HEADER AND CONFIGURATION CARDS.
C     OUD - OUTPUT UNIT FOR VALUES OF THE SLATER INTEGRALS ENTERING INTO
C           THE ENERGY EXPRESSION. IF OUD > 0, THE FULL ENERGY EXP-
C           RESSION WILL ALSO BE PRINTED; OTHERWISE THIS PRINTING IS
C           OMITTED.
C     OUF - OUTPUT UNIT FOR THE FUNCTION VALUES
C     OUH - OUTPUT UNIT FOR THE HAMILTONIAN MATRIX
C
C     IN EACH CASE, THE OUTPUT WILL BE OMITTED IF THE UNIT NUMBER IS SET
C     TO ZERO.
C
CARD 1. ATOM, TERM, Z, NO, NWF, NIT, NCFG, NF, NG, NR, NL, ORTHO, OMIT,
C       NEW  IN THE FORMAT(2A6,F6.0,I6,7I3,2L3,I3)
C
C     ATOM - IDENTIFYING LABEL
C     TERM - IDENTIFYING LABEL
C     Z    - ATOMIC NUMBER
C     NO   - MAXIMUM NUMBER OF POINTS IN THE RANGE OF THE FUNCTION
C            VARYING FROM 160 FOR A SMALL ATOM TO 220 FOR A LARGE
C            ATOM
C     NWF  - NUMBER OF FUNCTIONS
C     NIT  - NUMBER OF FUNCTIONS TO BE MADE SELF-CONSISTENT WITH THE
C            REMAINING INNER CORE TO BE KEPT "FROZEN"
C     NCFG - NUMBER OF CONFIGURATIONS
C     NF   - NUMBER OF FK INTEGRALS IN THE EXPRESSION FOR THE ENERGY
C     NG   - NUMBER OF GK INTEGRALS IN THE EXPRESSION FOR THE ENERGY
C     NR   - NUMBER OF RK INTEGRALS IN THE EXPRESSION FOR THE ENERGY
C     NL   - NUMBER OF L INTEGRALS IN THE EXPRESSION FOR THE ENERGY
C     ORTHO- LOGICAL VARIABLE: IF .FALSE. ONLY THE ORBITALS WITHIN A
C            CONFIGURATION WILL BE MADE ORTHOGONAL, OTHERWISE ALL
C            ORBITALS WITH DIFFERENT NL VALUES WILL BE MADE ORTHOGONAL.
C            WHEN NON-ORTHOGONAL ORBITALS ARE PRESENT, ORTHO MUST BE
C            .TRUE. IF A CORE ORBITAL IS TO BE DETERMINED WHICH SIMULT-
C            ANEOUSLY MUST BE ORTHOGONAL TO TWO NON-ORTHOGONAL ORBITALS
C            WITH THE SAME NL VALUES.  ORTHO MAY BE .FALSE. IF THE
C            COMMON CORE IS FIXED.  THE PROGRAM CANNOT DEAL WITH CASES
             WHERE AN ORBITAL TO BE DETERMINED MUST BE ORTHOGONAL TO
C            MORE THAN A SINGLE PAIR OF NON-ORTHOGONAL ORBITALS.
C     OMIT - LOGICAL VARIABLE: IF .FALSE. ORTHOGONALIZATION WILL OCCUR
C            ONLY AT THE END OF AN SCF CYCLE (WEAK ORTHOGONALITY),
C            THOUGH STRICT (STRONG) ORTHOGONALITY WILL BE MAINTAINED
C            WITH A FIXED CORE.  OTHERWISE, FUNCTIONS WILL BE KEPT
C            ORTHOGONAL AT ALL STAGES (STRONG ORTHOGONALITY).
C     NEW  - THE NUMBER OF NEW CONFIGURATIONS.  IF NEW = 0, ALL
C            CONFIGURATIONS WILL BE TREATED AS NEW, BUT WHEN NEW > 0,
C            AN MXM HAMILTONIAN MATRIX, WHERE M = (NCFG - NEW), WILL BE
C            LEFT UNCHANGED OR READ IN AS DATA IF IUH > 0.  IT IS
C            ASSUMED THE NEW CONFIGURATIONS HAVE BEEN ADDED AT THE END
C            OF THE LIST OF CONFIGURATIONS. THIS OPTION ALLOWS A CALC-
C            ULATION TO TREAT THE FIRST M CONFIGURATIONS AS PART OF A
C            FIXED OR FROZEN CORE.   THE RADIAL FUNCTIONS DEFINING THE
C            ASSOCIATED ENTRIES IN THE HAMILTONIAN MATRIX SHOULD THEN
C            ALSO BE KEPT FIXED.
C
C     THE MAXIMUM ALLOWED VALUE OF MANY OF THE ABOVE VARIABLES DEPENDS
C     ON THE DIMENSIONS OF ARRAYS.  THE MAXIMUM VALUES FOR THE PRESENT
C     PROGRAM ARE GIVEN BELOW:
C
C            VARIABLE      MAXIMUM VALUE
C            --------      -------------
C
C            NO            220
C            NWF            20
C            NCFG           40
C            NF + NG       200
C            NR            300
C            NL             20
C
CARD 2. FOR EACH I, I = 1,NCFG A CONFIGURATION CARD WITH
C
C     CONFIG1,CONFIG2,CONFIG3,CONFIG4, WT, WTL IN FORMAT( 4A6, F10.8, L1)
C
C     CONFIG - IDENTIFYING LABEL FOR THE CONFIGURATION
C     WT     - THE COEFFICIENT OR WEIGHT  FOR THE CONFIGURATION:
C              IF OMITTED, ALL CONFIGURATIONS HAVE EQUAL WEIGHT.
C              THE WEIGHTS ARE NORMALIZED TO UNITY BY THE PROGRAM.
C              IN AN MCHF CALCULATION IT IS IMPORTANT THAT THE INITIAL
C              EXPECTED OCCUPATION NUMBER OF ALL FUNCTIONS TO BE
C              DETERMINED BE DIFFERENT FROM ZERO, AND THAT FUNCTIONS
C              CONSTRAINED BY ORTHOGONALITY HAVE DIFFERING OCCUPATION
C              NUMBERS INITIALLY IF THEY WILL DIFFER IN THE FINAL
C              ANSWER.
C     WTL    - LOGICAL VARIABLE: IF .TRUE. THE THE WEIGHT IS TO BE
C              LEFT UNCHANGED FROM THE PREVIOUS CASE, OTHERWISE THE
C              VALUE OF WT IS TO BE USED.
C
CARD 3. FOR EACH I, I = 1,NWF A CARD WITH
C       EL(I),N(I),L(I),S(I),METH(I),ACC(I),IND(I),(QC(I,J),J=1,NCFG)
C       IN THE FORMAT(A3, 2I3, F6.2, I3, F3.1, I3, 15F3.0/(24X,15F3.0))
C
C     EL  - IDENTIFYING LABEL FOR THE ELECTRON
C     N   - PRINCIPAL QUANTUM NUMBER
C     L   - ANGULAR QUANTUM NUMBER
C     S   - SCREENING PARAMETER
C     METH- METHOD TO BE USED FOR SOLVING THE DIFFERENTIAL EQUATION
C           1 - METHOD 1 SOLVES A SINGLE BOUNDARY VALUE PROBLEM FOR AN
C               ACCEPTABLE SOLUTION WHICH NEED NOT BE NORMALIZED.
C           2 - METHOD 2 SOLVES A SINGLE BOUNDARY VALUE PROBLEM FOR AN
C               ACCEPTABLE SOLUTION WHICH IS NORMALIZED TO FIRST ORDER.
C               IF THE EXCHANGE FUNCTION IS IDENTICALLY ZERO, THE PROG-
C               RAM WILL AUTOMATICALLY SELECT METHOD 2.
C           3 - METHOD 3 IS SIMILAR TO METHOD 1 BUT OMITS ALL CHECKS
C               FOR ACCEPTABILITY. IT IS THE PREFERRED METHOD FOR
C               VIRTUAL ORBITALS WHOSE OCCUPATION NUMBER IS SMALL.
C     ACC - INITIAL ACCELERATING FACTOR, 0 .LE. ACC .LT. 1
C     IND - INDICATOR SPECIFYING THE TYPE OF INITIAL ESTIMATES
C              -1 - INPUT DATA TO BE READ FROM UNIT IUF
C               0 - SCREENED HYDROGENIC FUNCTIONS
C               1 - SAME AS RESULTS ALREADY IN MEMORY
C     QC  - NUMBER OF ELECTRONS I IN CONFIGURATION J.  A VALUE
C           OF -1 INDICATES THAT I'TH ORBITAL IS TO BE TREATED
C           AS OCCUPIED IN THE J'TH CONFIGURATION FOR ORTHO-
C           GONALITY PURPOSES WHEN ORTHO = .FALSE.
C
CARD 4. FOR EACH M, M = 1,NF (IF NF > 0) A CARD WITH
C       A, WW, K, I1, J1, I2, J2 IN THE FORMAT(F12.8,A1,I1,1X,2I2,1X,2I2,1X)
C
C     A      - COEFFICIENT OF THE FK INTEGRAL
C     W      - THE CHARACTER 'F'
C     K      - THE VALUE OF K
C     I1, J1 - THE I'TH RADIAL FUNCTION IN THE J'TH CONFIGURATION
C     I2, J2
C
CARD 5. FOR EACH M, M = 1,NG (IF NG > 0) A CARD WITH
C       B, W, K, I1, J1, I2, J2 IN THE FORMAT(F12.8,A1,I1,1X,2I2,1X,2I2)
C
C     B      - COEFFICIENT OF THE GK INTEGRAL
C     W      - THE CHARACTER 'G'
C     K      - THE VALUE OF K
C     I1, J1 - THE I'TH RADIAL FUNCTION IN THE J'TH CONFIGURATION
C     I2, J2
C
CARD 6. FOR EACH M, M = 1,NR (IF NR > 0) A CARD WITH
C       D, W, K, I1, I2, J1, I3, I4, J2, IO, JO, P
C       IN THE FORMAT(F12.8, 1X, I1, 1X, 3I2, 1X, 3I2, 1X,3(1X,I2))
C
C     D        - COEFFICIENT OF THE RK INTEGRAL
C     W        - THE CHARACTER 'R'
C     K        - THE VALUE OF K
C     I1,I2,J1 - THE I'TH RADIAL FUNCTION IN THE J'TH CONFIGURATION
C     I3,I4,J2
C     IO,JO    - RADIAL FUNCTIONS IN THE OVERLAP FACTOR <IO!JO>**P
C     P        - EXPONENT FOR THE OVERLAP FACTOR
C
CARD 7. FOR EACH M, M = 1,NL (IF NL > 0) A CARD WITH
C       C, W, K, I1, J1, I2, J2, IO, JO, P
C       IN THE FORMAT(F12.8, 2X, 2I2, 1X. 2I2, 1X, 3(1X,I2))
C
C     C      - COEFFICIENT OF THE L INTEGRAL
C     W      - THE CHARACTER 'L'
C     I1, J1 - THE I'TH RADIAL FUNCTION IN THE J'TH CONFIGURATION
C     I2, J2
C     IO,JO  - RADIAL FUNCTIONS IN THE OVERLAP FACTOR <IO!JO>**P
C     P      - EXPONENT FOR THE OVERLAP FACTOR.
C
CARD 8. FOR EACH I, I=1,NWF FOR WHICH IND(I) = -1, A RADIAL FUNCTION
C       WHICH WAS OUTPUT DURING A PREVIOUS RUN MUST BE READ FROM
C       UNIT IUF.  IF THIS UNIT IS THE SAME AS THE SYSTEM INPUT UNIT
C       FOR THE REST OF THE DATA, THE CARDS MUST BE INSERTED AT THIS
C       POINT IN THE ORDER IN WHICH THEY WILL BE READ.
C
CARD 9.  PRINT, NSCF, IC, ACFG, ID, CFGTOL, SCFTOL, LD
C       IN THE FORMAT(L3, 2I3, F3.1, I3, 2F6.1, L3)
C
C     PRINT - A LOGICAL VARIABLE: IF .TRUE. THE RADIAL FUNCTIONS WILL
C            BE PRINTED ON UNIT  6,  SEVEN FUNCTIONS PER PAGE.  THE
C            LOGICAL RECORD LENGTH FOR THIS UNIT MUST BE AT LEAST 130.
C     NSCF - THE MAXIMUM NUMBER OF CYCLES FOR THE SCF PROCESS.  IF
C            LEFT BLANK OR ZERO, A DEFAULT OF 12 IS ASSUMED.
C     IC   - THE NUMBER OF ADDITIONAL IMPROVEMENTS OF RADIAL FUNCTIONS
C            SELECTED ON THE BASIS OF GREATEST CHANGE, FOLLOWING A
C            SWEEP THROUGH THE SYSTEM OF EQUATIONS BUT PRIOR TO
C            REORTHOGONALIZATION, RECOMPUTATION OF OFF-DIAGONAL
C            ENERGY PARAMETERS, AND REDIAGONALIZATION OF THE ENERGY
C            MATRIX IN A MULTI-CONFIGURATION APPROXIMATION. IF = 0,
C            THE DEFAULT VALUE OF  3 + NIT/4 IS ASSUMED IN A SINGLE
C            CONFIGURATION APPROXIMATION.  THEN A CYCLE CONSISTING ONLY
C            OF SWEEPS THROUGH THE SYSTEM OF EQUATIONS REQUIRES THAT IC
C            BE SET TO -1.  WHEN NCFG > 1, THE ACTUAL VALUE IS USED.
C     ACFG - ACCELERATING PARAMETER TO BE APPLIED TO THE WEIGHTS
C            WT(I) AFTER AN ENERGY DIAGONALIZATION, 0 .LE. ACFG .LT. 1
C     ID   - IF NOT = 0, THE ENERGY MATRIX WILL BE COMPUTED BUT NOT
C            DIAGONALIZED AND THE WEIGHTS LEFT UNCHANGED.
C     CFGTOL- THE ENERGY CONVERGENCE TOLERANCE FOR A MULTI-CONFIGURATION
C             CALCULATION. IF = 0, A DEFAULT OF 1.D-10 IS ASSUMED.
C     SCFTOL- THE PARAMETER DEFINING THE SELF-CONSISTENCY TOLERANCE
C             FOR RADIAL FUNCTIONS.  IF = 0, A DEFAULT VALUE OF
C             1.D-7 IS ASSUMED.
C     LD    - A LOGICAL VARIABLE: IF .TRUE. THE ENERGY MATRIX IS DIAG-
C             ONALIZED BEFORE THE SCF ITERATIONS BEGIN.  THIS IS RECOM-
C             MENDED ONLY WHEN THE RADIAL FUNCTIONS ARE KNOWN TO GOOD
C             ACCURACY.
CARD 10.  AT THIS POINT, IF IUH > 0, AN MXM HAMILTONIAN MATRIX AS OUTPUT
C         FROM SOME PREVIOUS CALCULATION SHOULD BE INSERTED, WHERE
C         M = (NCFG - NEW).  DURING THE CALCULATION THIS PORTION
C         OF THE INTERACTION MATRIX WILL BE LEFT UNCHANGED UNLESS
C         DATA CARDS ARE INCLUDED FOR THIS PORTION OF THE MATRIX.
C         THE TERMS REPRESENTED BY SUCH DATA CARDS WILL BE ADDED
C         TO THE INITIAL MATRIX.   WHEN IUH = 0, IT IS ASSUMED THAT
C         THIS PORTION OF THE MATRIX IS ALREADY IN MEMORY.
C
CARD 10. END, NEXT, ATOM, ZZ, (ACC(I), I=1,NWF)
C        IN THE FORMAT(A1, I2, A6, F6.0, 20F3.1)
C
C     END  - SPECIAL SYMBOL '*' DENOTING THE END OF A CASE.  THE PROGRAM
C            ASSUMES THAT THE NEXT CARD, IF ANY, IS A CARD OF TYPE 1.
C            (THE ASTERISK IS IMPORTANT ONLY IN THE CASE OF A FAILURE
C            TO CONVERGE WHEN THE PROGRAM ATTEMPTS TO FIND THE BEGINNING
C            OF THE NEXT CASE.)
C     NEXT - A VARIABLE DETERMINING SUBSEQUENT ACTION. IF NEXT = 0, THE
C            CASE HAS COMPLETED SUCCESSFULLY AND THE FOLLOWING CARD, IF
C            ANY, IS ASSUMED TO BE A CARD OF TYPE 1.  IF NEXT = 1,  THE
C            PROGRAM WILL SCALE PRESENT RESULTS FOR ATOMIC NUMBER Z TO
C            THOSE FOR ATOMIC NUMBER ZZ, USING A SCREENED HYDROGENIC
C            SCALING LAW, AND REPEAT THE CALCULATION FOR THE NEW CASE.
C            THE NEXT CARD WILL BE ASSUMED TO BE OF TYPE 9.
C     ZZ   - THE NEW ATOMIC NUMBER FOR THE NEXT CASE.
C     ACC  - THE NEW ACCELERATING PARAMETERS FOR THE NEXT CASE
C
C     ALL CALCULATIONS FOR AN ISOELECTRONIC SEQUENCE ARE ASSUMED TO BE
C     ONE CASE.   SEVERAL EXAMPLES OF INPUT DATA NOW FOLLOW BUT NOTE
C     THAT THE DATA CARDS MUST BE REMOVED BEFORE THE PROGRAM CAN BE
C     COMPILED.
C
C     ------------------------------------------------------------------
C     2-1     E X A M P L E   1
C     ------------------------------------------------------------------
C
C     THE FIRST EXAMPLE ILLUSTRATES HOW DATA CAN BE SET UP FOR AN
C     ISOELECTRONIC SEQUENCE.  NOTE THAT FOR EACH ATOM OR ION, THE
C     SLATER INTEGRALS AND RADIAL FUNCTIONS ARE PRINTED.  THE LATTER
C     ALSO ARE OUTPUT, A FUNCTION AT A TIME, FOR FUTURE INPUT.
C
  1  1  0  0
  6  6  7  0
 BE    1S      4.    180  2  2  1
  1S2/2S2
 1S  1  0  0.0   1  0  0  2
 2S  2  0  3.0   1  0  0  2
  T 12  4
  1  B+    5.0
  T 12  4
  1 C+2    6.0
  T 12  4
  1 O+4    8.0
  T 12  4
  1 NA+7  11.0
  T 12  4
  1 P+11  15.0
  T 12  4
  1 CA+16 20.0
  T 12  4
  1 MN+21 25.0
  T 12  4
  1 ZN+26 30.0
  T 12  4
*
C
C     THOUGH RESULTS ARE MEANINGFUL PHYSICALLY ONLY FOR INTEGRAL
C     VALUES OF Z, A USEFUL FEATURE WHEN DOING CALCULATIONS FOR
C     NEGATIVE IONS WHERE INITIAL ESTIMATES ARE NOT WELL KNOWN, IS
C     THE ABILITY TO TURN OFF THE NUCLEAR CHARGE IN FRACTIONAL STEPS,
C     THEREBY APPROACHING THE RELATIVELY UNSTABLE STATE WITH GOOD
C     INITIAL ESTIMATES.
C
C     ------------------------------------------------------------------
C     2-2    E X A M P L E    2
C     ------------------------------------------------------------------
C
C     THE SECOND EXAMPLE ILLUSTRATES A FIXED CORE CALCULATION.  IN THE
C     FIRST CASE, HARTREE-FOCK CALCULATIONS ARE PERFORMED FOR THE NA+
C     CORE.  THEN, WITH THESE FUNCTIONS FIXED AND STILL IN MEMORY, A
C     FIXED CORE CALCULATION IS PERFORMED FIRST FOR 3S AND THEN FOR 3P.
C     IN THIS CASE NO CALCULATIONS ARE SUMMARIZED  NOR ARE ANY RESULTS
C     PUNCHED. NOTE ALSO THE ZERO OCCUPATION NUMBER FOR 3S IN THE
C     CALCULATION FOR 3P.  THIS IS ALLOWED AS LONG AS THE ASSOCIATED
C     RADIAL FUNCTION IS NOT INCLUDED IN THE SET OF FUNCTIONS BEING
C     MADE SELF-CONSISTENT.
C
  1  1  0  0
  0  0  0  0
 NA+   1S     11.    190  3  3  1
  2S2/2P6
 1S  1  0  0.0   1  0  0  2
 2S  2  0  2.0   1  0  0  2
 2P  2  1  7.0   1  0  0  6
  F 10 10
*
 NA    2S     11.    190  4  1  1
  2S2/2P6/3S
 1S  1  0  0.0   1  0  1  2
 2S  2  0  2.0   1  0  1  2
 2P  2  1  7.0   1  0  1  6
 3S  3  0 10.0   1  0  0  1
  F 10 2
*
 NA    2P     11.    190  5  1  1
  2S2/2P6/3P
 1S  1  0  0.0   1  0  1  2
 2S  2  0  2.0   1  0  1  2
 2P  2  1  7.0   1  0  1  6
 3S  3  0 10.0   1  0  1  0
 3P  3  1 10.0   1  0  0  1
  F 10 2
*
C
C     ------------------------------------------------------------------
C     2-3    E X A M P L E    3
C     ------------------------------------------------------------------
C
C     THIS EXAMPLE ILLUSTRATES THE USE OF MULTIPLE ORBITALS OF THE SAME
C     TYPE.   THIS FEATURE IS RESTRICTED TO CASES WHERE THE INTERACTION
C     BETWEEN CONFIGURATIONS RESULTS IN TERMS WITH AT MOST ONE OVERLAP
C     INTEGRAL.   THESE ARE ALLOWED ONLY FOR RK AND L INTEGRALS AND SO
C     OCCASSIONALLY FK OR GK INTEGRALS MUST BE RE-EXPRESSED AS RK
C     INTEGRALS.
C
C
  1  1  0  0
  0  0  0  0
 B     2P      5.    180  4  4  2  1  0  1
  2S2/2P                 1.0
  2P*3                    0.3
 1S  1  0  0.0   1  0  0  2  2
 2S  2  0  2.0   1  0  0  2
 2P  2  1  4.0   1  0  0  1
2P*  2  1  3.0   3  0  0  0  3
 0.240000000F2( 4 2, 4 2)
 -0.94280904R1( 2 2 1, 4 4 2)< 3! 4> 1
  F  8  1  0  0 .1E-7 .1E-5
*
C
C
C     IN THE ABOVE EXAMPLE THE CFGTOL AND SCFTOL PARAMETERS HAVE BEEN
C     RESET TO LARGER  VALUES THAN THE DEFAULT VALUES AND NO FUNCTIONS
C     ARE PUNCHED.   THIS APPROACH IS USEFUL WHEN A TRIAL CALCULATION
C     IS BEING PERFORMED.
C
C     IN MORE COMPLEX CASES, MORE RESTRICTIONS ARE PRESENT.  NORMALLY
C     AN OFF-DIAGONAL ENERGY PARAMETER CAN BE COMPUTED DIRECTLY FROM
C     A PAIR OF RADIAL EQUATIONS (SEE SEC. 7-3), BUT WHEN NON-ORTHOG-
C     ONAL ORBITALS ARE PRESENT, INDICATED BY THE FACT THAT THEIR NL
C     VALUES ARE THE SAME, IT MAY BE NECESSARY TO SOLVE A SYSTEM OF
C     EQUATIONS FOR SETS OF PARAMETERS.  WHEN ORTHO = .FALSE., THE
C     PROGRAM ASSUMES OFF-DIAGONAL PARAMETERS CAN BE COMPUTED FROM A
C     SINGLE PAIR OF EQUATIONS.  WHEN ORTHO = .TRUE., THE PROGRAM
C     CHECKS IF OTHER ORBITALS ARE PRESENT, NON-ORTHOGONAL TO EITHER
C     ONE OF THE PAIR.  AT MOST ONE SUCH ORBITAL FOR EACH MEMBER CAN
C     BE ACCOMMODATED.  THE IMPLICATION OF THESE RESTRICTIONS CAN BE
C     DESCRIBED FOR THE MCHF CALCULATION --
C             2P6.(3S.3P  +  3P'.3D )
C     IF 2P IS DETERMINED VARIATIONALLY IT MUST BE ORTHOGONAL TO BOTH
C     3P AND 3P' WHICH ARE NON-ORTHOGONAL.  HENCE A SYSTEM OF EQUATIONS
C     MUST BE SOLVED AND WE NEED ORTHO = .TRUE.  ON THE OTHER HAND, IF
C     2P WERE PART OF THE FIXED CORE, THE VALUE OF ORTHO WOULD NOT BE
C     IMPORTANT.  THE CALCULATION FOR
C             2P6.(3S.3P + 4S.4P  + 3P'.3D + 4P'.4D )
C     CAN ONLY BE PERFORMED CORRECTLY WITH 2P PART OF A FIXED CORE.
C     ORTHO MUST BE .FALSE. OTHERWISE ALL FUNCTIONS WITH DIFFERENT NL
C     VALUES WOULD BE MADE ORTHOGONAL.  THE -1 OPTION MUST BE USED TO
C     INCLUDE 4S,4P IN CONFIGURATION 1, 4P',4D IN CONFIGURATION 3
C     FOR ORTHOGONALITY PURPOSES.
C
C
C     ------------------------------------------------------------------
C     2-4    E X A M P L E    4
C    -------------------------------------------------------------------
C
C     THE EXAMPLE BELOW IS A TWO CONFIGURATION PROBLEM WHERE THE INTER-
C     ACTION IS SMALL AND ALL FUNCTIONS MUST BE ORTHOGONAL.  IN SUCH A
C     CALCULATION IT IS IMPORTANT THAT THE FUNCTIONS DEFINING THE DOM-
C     INANT CONFIGURATION BE FAIRLY ACCURATE AND SO A ONE CONFIGURATION
C     CALCULATION IS USED FOR DETERMINING THE INITIAL ESTIMATES.
C
C     THE INTERACTION IN THIS CASE IS SMALL RESULTING IN A SHALLOW
C     ENERGY MINIMUM.  THIS COMBINED WITH THE MANY ORTHOGONALITY CON-
C     STRAINTS MAKES CONVERGENCE DIFFICULT.  THE PROGRAM PRINTS OUT
C     SEVERAL DIRE MESSAGES BUT THESE DISAPPEAR AS CONVERGENCE SETS IN.
C
  1  1  0  0
  0  0  0  0
 HE    3S      2.    180  2  2  1  0  1  0
  1S/2S
 1S  1  0  0.0   1  0  0  1
 2S  2  0  1.0   1  0  0  1
 -.500000000G0( 1 1, 2 1)
  F 12 -1
*
 HE    3S      2.    180  4  2  2  0  2  2  0  T  T
  1S/2S                  0.9965624
 3S/4S                   -.0016
 1S  1  0  0.0   1  0  1  1
 2S  2  0  1.0   1  0  1  1
 3S  3  0 -5.0   3  0  0  0  1
 4S  4  0 -8.7   3  0  0  0  1
 -.500000000G0( 1 1, 2 1)
 -.5        G0( 3 2, 4 2)
 2.0        R0( 1 2 1, 3 4 2)
-2.0        R0( 1 2 1, 4 3 2)
  F 15  1  0  0 .1E-7 .1E-6
*
C
C     NOTE THAT WHEN NO OVERLAP INTEGRALS ARE PRESENT, THEY CAN SIMPLY
C     BE OMITTED.  ALSO, NEGATIVE SCREENING PARAMETERS MAY BE USED TO
C     TO CONTRACT THE VIRTUAL ORBITALS.
C
C
C     ------------------------------------------------------------------
C     2-5    E X A M P L E    5
C     -----------------------------------------------------------------
C
C     ONE OF THE MORE DIFFICULT CASES, HISTORICALLY WAS 1S2S 1S OF HE.
C     THIS IS AN EXAMPLE WHERE LARGE OFF-DIAGONAL ENERGY PARAMETERS
C     OCCUR BECAUSE OF THE ORTHOGONALITY CONSTRAINT, THE EFFECT OF
C     WHICH IS TO ROTATE THE USUAL 1S, 2S ORBITAL BASIS.   ON THE
C     OTHER HAND, THE 1S2S 3S CALCULATION IS A PARTICULARLY SIMPLE
C     ONE.   THE DATA BELOW DESCRIBES A CALCULATION IN WHICH THE
C     OUTPUT FOR 3S DEFINES THE INITIAL ESTIMATES FOR THE 1S STATE.
C
C     IN THIS CASE, THE 1S STATE IS NOT THE LOWEST STATE OF A GIVEN
C     SYMMETRY AND THE HARTREE-FOCK APPROXIMATION IS NOT A PARTICULARLY
C     GOOD ONE, THE TOTAL ENERGY BEING CONSIDERABLY BELOW THE OBSERVED.
C     AN MCHF APPROXIMATION WHICH INCLUDES  1S2 1S  YIELDS A
C     MUCH BETTER RESULT.  SUCH A CALCULATION FOLLOWS THE SINGLE
C     CONFIGURATION CASE BELOW, WITH 3S FUNCTIONS AGAIN SERVING
C     AS INITIAL ESTIMATES.
C
C
  1  1  0  0
  0  0  0  0
 HE    3S      2.    180  2  2  1  0  1  0
  1S/2S
 1S  1  0  0.0   1  0  0  1
 2S  2  0  1.0   1  0  0  1
 -.500000000G0( 1 1, 2 1)
  F 12 -1
*
 HE    1S      2.    180  2  2  1  0  1  0
  1S/2S
 1S  1  0  0.0   1  0  1  1
 2S  2  0  1.0   1  0  1  1
 1.500000000G0( 1 1, 2 1)
  F 12 -1
*
 HE    3S      2.    180  2  2  1  0  1  0
  1S/2S
 1S  1  0  0.0   1  0  1  1
 2S  2  0  1.0   1  0  1  1
 -.500000000G0( 1 1, 2 1)
  F 12 -1
*
 HE    1S      2.    180  2  2  2  0  1  1  1  F  T
  1S/2S                  0.9965624
  1S2                      .114
 1S  1  0  0.0   1  0  1  1  2
 2S  2  0  1.0   1  0  1  1
 1.500000000G0( 1 1, 2 1)
 2.82842712 R0( 1 2 1, 1 1 2)
 -1.41421356L( 2 1, 1 2)
  F  9 -1 .3  0 1.E-7 .1E-6  T
*
C
C
C     IN THIS CASE, THE CONFIGURATIONS DIFFER BY EXACTLY ONE ELECTRON
C     AND THE INTERACTION NOW ALSO INVOLVES AN L INTEGRAL.   THE
C     CALCULATIONS HAVE BEEN SET UP IN SUCH A WAY THAT FIRST 1S, THEN
C     2S ARE IMPROVED  (IN THE MCHF CASE, 2S IS KEPT STRICTLY
C     ORTHOGONAL TO 1S), AFTER WHICH THE FUNCTIONS ARE ROTATED TO
C     SATISFY THE STATIONARY CONDITION, AND THE ENERGY MATRIX
C     DIAGONALIZED.   THE ROTATIONS SEEM TO INTRODUCE OSCILLATIONS
C     IN THIS CASE AND SO ACFG WAS SET TO 0.3 IN ORDER TO DAMP OUT
C     THESE OSCILLATIONS.
C
C
C     ------------------------------------------------------------------
C     2-6    E X A M P L E    6
C     -----------------------------------------------------------------
C
C     THIS EXAMPLE SHOWS HOW A SIXTH CONFIGURATION CAN BE ADDED TO AN
C     INTERACTION MATRIX, WHERE THE MATRIX WAS OUTPUT DURING A PREVIOUS
C     CALCULATION.  IT IS ASSUMED THAT RADIAL FUNCTIONS CAN BE READ
C     FROM UNIT 8.
C
  1  1  2  1
  6  0  6  6
 AR+2  3S     18.    200  6  0  6  2  3  6  0  F  F  1
 2P5/3P5                 0.9920873
 2S/3S                   0.0364112
 3S/3P5/3D(1P)           0.1149757
 3S/3P5/3D(3P)          -0.0348588
 3S/3P5/3D(3P)          -0.0015988
 2S/3P4/3D              -0.018
 1S  1  0  0.0   1  0 -1  2  2  2  2  2  2
 2S  2  0  3.0   1  0 -1  2  1  2  2  2  1
 2P  2  1  7.0   1  0 -1  5  6  5  5  5  6
 3S  3  0 10.0   1  0 -1  2  1  1  1  1  2
 3P  3  1 10.0   1  0 -1  5  6  5  5  5  4
 3D  3  2 12.0   3  0 -1  0  0  1  1  1  1
  0.12000000F2( 506, 506)
 -0.40000000F2( 506, 606)
  0.53333333G1( 506, 606)
 -0.08571429G3( 506, 606)
 -0.10000000G2( 606, 206)
  0.94280904R1( 6 3 6, 5 2 1)
 -1.63299316R1( 4 6 6, 5 5 2)
 -0.94280904R1( 4 3 6, 5 2 3)
  1.41421356R0( 4 3 6, 2 5 3)
 -0.81649658R0( 4 3 6, 2 5 4)
 -2.30940108R0( 4 3 6, 2 5 5)
  f  0  0  0  0 1.e-8 .1e-5
  -516.5748431
    -0.1543388  -513.0822716
    -0.2328091     0.1413721  -514.7085685
     0.1012540    -0.2399579    -0.2016125  -514.6445872
     0.0062108    -0.0069378    -0.0322798    -0.0086021  -515.0489374
*
C
C     NOTICE THAT THE DATA CARDS FOR THE ENERGY EXPRESSION NOW NEED
C     REFER ONLY TO THE NEW CONFIGURATION, ALL OTHER ENTRIES OF THE
C     INTERACTION MATRIX BEING KEPT FIXED.   THIS CAN BE USED TO
C     ADVANTAGE IN VERY LARGE PROBLEMS WHERE THE NUMBER OF FK, GK, OR
C     RK INTEGRALS MIGHT EXCEED THE MAXIMUM ALLOWED BY THE DIMENSIONS
C     OF THE ARRAYS.  IN THIS WAY ONE CAN, IN EFFECT, EVALUATE PORTIONS
C     OF THE MATRIX AT A TIME.
C
C
C     ------------------------------------------------------------------
C     2-7        P E R F O R M A N C E   T E S T   D A T A
C     ------------------------------------------------------------------
C
C
C     AN INDICATION OF THE ACCURACY OF THE NUMERICAL PROCEDURE USED IN
C     THIS PROGRAM IS GIVEN IN SEC. 6-9 AND ALSO COMPUT. PHYS. COMMUN.
C     4, 107 (1972).   THESE RESULTS ALL PERTAIN TO THE HYDROGENIC
C     PROBLEM.  ADDITIONAL SOURCES OF ERRORS ENTER INTO THE GENERAL HF
C     PROBLEM.  THE RESULTS FROM THE TEST DATA PROVIDED BELOW, INDICATE
C     THE LIMITS OF ACCURACY ON THE IBM 360/370 SERIES, AND ALSO PROVIDE
C     INFORMATION ABOUT THE RATE OF CONVERGENCE FOR OUR METHODS.  THE
C     CASES SELECTED  ARE TYPICAL TEST CASES OFTEN USED FOR EVALUATING
C     A METHOD.
C
C
  1  1  0  0
  0  0  0  0
 HE    1S      2.    150  1  1  1
  1S2
 1S  1  0  0.0   1  0  0  2
  F 10 10  0  0 .1E-9 .1E-9
*
 HE    1P      2.    180  2  2  1  0  1
  1S/2P
 1S  1  0  0.0   1  0  0  1
 2P  2  1  1.0   1  0  0  1
  0.50000000G1( 1 1, 2 1)
  F 10 10  0  0.1E-12.1E-12
*
 HE    3S      2.    180  2  2  1  0  1  0
  1S/2S
 1S  1  0  0.0   1  0  0  1
 2S  2  0  1.0   1  0  0  1
 -.500000000G0( 1 1, 2 1)
  F 12 -1  0  0 .1E-9 .1E-9
*
 HE    1S      2.    180  2  2  1  0  1  0
  1S/2S
 1S  1  0  0.0   1  0  1  1
 2S  2  0  1.0   1  0  1  1
 1.500000000G0( 1 1, 2 1)
  F 12 -1  0  0 .1E-9 .1E-9
*
 LI    4S      3.    200  3  3  1  0  3  0
  1S/2S/3S
 1S  1  0  0.0   1  0  0  1
 2S  2  0  1.0   1  0  0  1
 3S  3  0  2.0   1  0  0  1
 -.500000000G0( 1 1, 2 1)
 -.500000000G0( 1 1, 3 1)
 -.500000000G0( 2 1, 3 1)
  F 12 -1  0  0 .1E-9 .1E-9
*
 W+64  1S     74.    200  3  3  1
  1S2/2S2/2P6
 1S  1  0  0.0   1  0  0  2
 2S  2  0  2.0   1  0  0  2
 2P  2  1  7.0   1  0  0  6
  F 12 12  0  0.1E-11.1E-11
*
C
C
C     THE FOLLOWING  TABLE SUMMARIZES THE RESULTS.
C
C              T A B L E   OF   R E S U L T S
C
C          -E       - TOTAL ENERGY IN ATOMIC UNITS
C          PE/KE    - RATIO OF POTENTIAL AND KINETIC ENERGY
C          DPM      - MAXIMUM DIFFERENCE BETWEEN THE FUNCTIONS OF THE
C                     PREVIOUS AND CURRENT SCF ITERATION
C          NXCH     - NUMBER OF EXCHANGE FUNCTIONS COMPUTED
C
C
C                               -E         (PE/KE)+2   DPM      NXCH
C   1. HE  1S2 1S              2.861679995    4.D-9  1.38D-10  13( 8)
C   2. HE  1S/2P 1P            2.122464215    2.D-9  2.33D-14  19( 7)
C   3. HE  1S/2S 3S            2.174250777  -12.D-9  1.49D-08  18(12)
C   4. HE  1S/2S 1S            2.169854456   -1.D-9  7.37D-09  24(20)
C   5. LI  1S/2S/3S 4S         5.204454130  -16.D-9  4.29D-09  27(21)
C   6. W+64 1S2/2S2/2P6 1S 10318.516188029    1.D-9  2.00D-12  24(12)
C
C     THE METHODS USED IN THE PROGRAM RELY ON PROPERTIES OF THE HF
C     EQUATIONS, PARTICULARLY WHEN SATISFYING THE ORTHOGONALITY REQUIR-
C     EMENT.  THE DISCRETIZED APPROXIMATION WILL HAVE THESE PROPERTIES
C     ONLY TO LIMITED ACCURACY.  FOR EXAMPLE, THE DISCRETIZED PROBLEM
C     FOR HE 1S/2S 3S WITH OFF-DIAGONAL ENERGY PARAMTETERS EQUAL TO
C     ZERO, HAS SOLUTIONS FOR WHICH <1S!2S> = 1.4D-8.  THE ORTHOGON-
C     IZATION PROCESS THEN LIMITS THE APPARENT SCF CONVERGENCE.  HOW-
C     EVER, A SMALLER DPM DOES NOT NECESSARILY QUARANTEE GREATER ACC-
C     URACY.  A BETTER INDICATION OF ACCURACY IS THE RATIO, (PE/KE)+2,
C     WHICH FOR EXACT SOLUTIONS WOULD BE ZERO.  IN MOST CASES THE
C     MAGNITUDE OF THIS QUANTITY IS SEVERAL UNITS IN THE NINTH DECIMAL
C     PLACE.
C
C     AN INDICATION OF THE EFFECTIVENESS OF THE PROGRAM CAN BE OBTAINED
C     FROM THE NUMBER OF TIMES AN EXCHANGE FUNCTION HAS TO BE COMPUTED.
C     (IN LARGE ATOMS MOST OF THE COMPUTATION TIME IS DEVOTED TO THE
C     EVALUATION OF EXCHANGE FUNCTIONS, AND SO THIS IS A REASONABLY
C     CONVENIENT MACHINE INDEPENDENT MEASURE OF EFFICIENCY, WHERE THE
C     MOST EFFICIENT PROGRAM ACHIEVES A GIVEN ACCURACY WITH THE
C     LEAST AMOUNT OF COMPUTATION.)  THE FIRST NUMBER UNDER THE NXCH
C     COLUMN IS THE ACTUAL NUMBER OF CALLS TO XCH MADE BY THE PROGRAM,
C     BUT BECAUSE OF THE HIGH ACCURACY REQUESTED, SEVERAL OF THESE DID
C     NOT IMPROVE THE DEGREE OF SELF-CONSISTENCY.  IN PARENTHESES IS
C     THE NUMBER OF CALLS TO XCH REQUIRED FOR AN A POSTERIORI SELF-
C     CONSISTENCY OF AT LEAST 8.5D-8, WHERE THE DEGREE OF SELF-CONSIST-
C     ENCY IS NOW THE MAXIMUM DIFFERENCE BETWEEN THE CURRENT FUNCTION
C     AND ITS NEXT SCF ITERATE.  NOTICE THE VERY RAPID RATE OF CONVER-
C     GENCE FOR HIGHLY IONIZED SYSTEMS.  FOR W+64, AN AVERAGE OF 4.33
C     IMPROVEMENTS PER FUNCTION PRODUCED AN A POSTERIORI  DEGREE OF
C     SELF-CONSISTENCY OF AT LEAST 6.6D-9 .  A MORE DETAILED STUDY OF
C     THE RATE OF CONVERGENCE FOR THE VARIOUS CASES WILL APPEAR IN THE
C     JOURNAL OF COMPUTATIONAL PHYSICS, 1977.
C
▶EOF◀