Gaussian's output

Gaussian's output analysis

G09 Input deck.

%chk=your_file.chk                       ! set path to save your checkpoint file.

%mem=1GB                                 ! Total memory usage

%nprocs=1                                ! Core

#P HF/STO-3G scf=tight pop=regular       ! Calculation set up

HF/STO-3G//HF/STO-3G sp formaldehyde     ! comment

0 1                                      ! charge & multiplicity

C1                                       ! atom coordinate for whole molecule in z-format

O2  1  r2

H3  1  r3  2  a3

H4  1  r3  2  a3  3  180.0

r2=1.21672286

r3=1.10137241

a3=122.73666566

Optimized structure in each step of calculation.

Optimization completed.

The deck below is example of truncated gaussian output that provides you the optimized parameters that respect to your optimized molecule. The R, A, and D variables in each line are bond distance, atom angle, dihedral parameters, respectively,

-- Stationary point found.

             ----------------------------

               ! Optimized Parameters !

               ! (Angstroms and          Degrees) !

------------------------ -------------------------

! Name  Definition       Value   Derivative Info.

------------------------------------------------------

! R1     R(2,1)          1.1843      -DE/DX =

! R2     R(3,1)          1.0915      -DE/DX =

! R3     R(4,1)          1.0915      -DE/DX =

! A1     A(2,1,3)        122.1304    -DE/DX =

! A2     A(2,1,4)        122.1304    -DE/DX =

! A3     A(3,1,4)        115.7391     -DE/DX =

! D1     D(2,4,1,3)      180.         -DE/DX =

------------------------------------------------------

Molecular Orbital

There are only four virtual orbitals and only those are printed. The orbital coefficients are given with respect to the molecule in its "Standard orientation" given at the beginning of the output file. The system is oriented such that the principal axis of the systems runs along the z-axis and that all atoms of the system are located in the yz-plane:

                         Standard orientation:

 ---------------------------------------------------------------------

 Center     Atomic     Atomic              Coordinates (Angstroms)

 Number     Number      Type              X           Y           Z

 ---------------------------------------------------------------------

    1          6             0        0.000000    0.000000   -0.533912

    2          8             0        0.000000    0.000000    0.682811

    3          1             0        0.000000    0.926436   -1.129510

    4          1             0        0.000000   -0.926436   -1.129510

 ---------------------------------------------------------------------

Lowest energy

Look back in the output file about 25 - 30 lines before the "optimization completed" phrase. You should see the SCF energy of the optimized structure.

SCF Done: E(RHF) = -113.866331170 A.U. after 12 cycles

Tips: you could use 'grep' command in Linux to search and print you out with entire optimized energies.

Enthalpy energy

Temperature    298.150 Kelvin.   Pressure     1.00000 Atm.

Zero-point correction=                             .029201 (Hartree/Particle)

Thermal correction to Energy=                      .032054

Thermal correction to Enthalpy=                    .032999

Thermal correction to Gibbs Free Energy=           .008244

Sum of electronic and zero-point Energies=     -113.837130

Sum of electronic and thermal Energies=        -113.834277

Sum of electronic and thermal Enthalpies=      -113.833333

Sum of electronic and thermal Free Energies=   -113.858087

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