| 1 | FUNCTION H2ENER(V,J) |
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| 2 | C H2ENER SUBROUTINE OF THE INV PROGRAM. COMPUTES THE ENERGY |
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| 3 | C (IN CM-1) OF A VIBRATION-ROTATION STATE OF A HYDROGEN MOLECULE. |
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| 4 | C THE VIBRATION QUANTUM NUMBER IS V, AND THE QUANTUM NUMBER FOR |
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| 5 | C THE RIGID BODY ANGULAR MOMENTUM IS J (A REAL*4 QUANTITY). |
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| 6 | C THE FIRST LINE OF THE FORMULA FOR E IS THE CONTRIBUTION FROM |
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| 7 | C PURE VIBRATION, INCLUDING ANHARMONIC TERMS. THE OTHER LINES |
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| 8 | C ACCOUNT FOR COUPLED VIBRATION AND ROTATION, INCLUDING |
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| 9 | C CENTRIFUGAL DISTORTION. (THE (J(J+1))**2 AND (J(J+1))**3 |
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| 10 | C PROVIDE FOR CENTRIFUGAL DISTORTION; THE VP AND VP**2 IN THE |
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| 11 | C ROTATION TERMS PROVIDE FOR COUPLING BETWEEN VIBRATION AND |
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| 12 | C ROTATION.) |
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| 13 | C THE FORMULA OF COHEN AND BIRNBAUM(1981), |
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| 14 | C NU = 59.3392*(J(J+1)) - 0.04599*(J(J+1))**2 |
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| 15 | C + 0.000052*(J(J+1))**3 CM-1, |
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| 16 | C IS A SPECIAL CASE OF THE FORMULA USED HERE, OBTAINED BY |
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| 17 | C SETTING V=0 (IE., VP = 1/2); THE VP TERMS IN THE VIBRATION- |
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| 18 | C ROTATION CONTRIBUTIONS CORRECT THE INITIAL TERMS TO |
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| 19 | C PRODUCE THE COEFFICIENTS IN THE COHEN AND BIRNBAUM FORMULA. |
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| 20 | C FOR THE COLD ATMOSPHERES OF THE OUTER PLANETS, THE SIGNIF- |
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| 21 | C ICANTLY POPULATED LEVELS HAVE V=0. |
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| 22 | C |
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| 23 | C*********************************************************************** |
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| 24 | C |
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| 25 | IMPLICIT REAL (A-H,O-Z) |
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| 26 | REAL J,JP |
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| 27 | C |
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| 28 | VP = V + 0.5 |
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| 29 | JP = J + 1.0 |
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| 30 | E = 4400.39*VP - 120.815*VP**2 + 0.7242*VP**3 + |
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| 31 | A (60.841 - 3.0177*VP + 0.0286*VP**2)*J*JP - |
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| 32 | B (0.04684 - 0.00171*VP + 3.1E-05*VP**2)*J**2*JP**2 + |
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| 33 | C 5.2E-05*J**3*JP**3 - 2170.08 |
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| 34 | H2ENER = E |
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| 35 | RETURN |
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| 36 | END |
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