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55.1.3 Examples

The following input example for a grid based calculation of anharmonic frequencies and intensities (1) optimizes the geometry of water, (2) computes the harmonic frequencies, (3) generates a potential energy surface around the equilibrium structure, (4) computes the vibrational wave function and the infrared intensities at the VSCF level, and finally (5) a VCI calculation will be performed. Vibrational angular momentum terms (VAM) are included even for the non-diagonal elements of the VCI matrix.

memory,20,m
basis=vdz
orient,mass
geometry={
   3
Water
O          0.0675762564        0.0000000000       -1.3259214590
H         -0.4362118830       -0.7612267436       -1.7014971211
H         -0.4362118830        0.7612267436       -1.7014971211
}

mass,iso

hf
mp2
optg                                     !(1) optimizes the geometry
frequencies,symm=auto                   !(2) compute harmonic frequencies

label1
{hf
start,atden}
{mp2
cphf,1}

{surf,start1D=label1,sym=auto            !(3) generate potential energy surface
 intensity,dipole=2}
vscf                                     !(4) do a VSCF calculation
vci,vam=3                                !(5) do a VCI calculation
put,irspec,irspec.gnu                    !writes a gnuplot file to plot an IR
                                         !spectrum of the last VCI calculation

The following input example for a polynomial based calculation of anharmonic frequencies and intensities (1) optimizes the geometry of water, (2) computes the harmonic frequencies,(3) generates a potential energy surface around the equilibrium structure, (4) converts the potential energy surface into a polynomial representation (5) computes the nuclear wave function and the infrared intensities at the VSCF level, and finally (6) performs a VCI calculation. Vibrational angular momentum terms (VAM) are included even for the non-diagonal elements of the VCI matrix.

memory,20,m
basis=vdz
orient,mass
geometry={
   3
Water
O          0.0675762564        0.0000000000       -1.3259214590
H         -0.4362118830       -0.7612267436       -1.7014971211
H         -0.4362118830        0.7612267436       -1.7014971211
}

mass,iso

hf
mp2
optg                                     !(1) optimizes the geometry
frequencies,symm=auto                   !(2) compute harmonic frequencies

label1
{hf
start,atden}
{mp2
cphf,1}

{surf,start1D=label1,sym=auto            !(3) generate potential energy surface
 intensity,dipole=2}
poly,dipole=1                            !(4) converts potential energy surface
                                         !    to a polynomial representation
vscf,type=poly                           !(5) do a VSCF calculation
vci,type=poly,vam=3                      !(6) do a VCI calculation
put,irspec,irspec.gnu                    !writes a gnuplot file to plot an IR
                                         !spectrum of the last VCI calculation



Next: 55.2 The vibrational MP2 Up: 55.1 The VCI program Previous: 55.1.2 Explicit definition of   Contents   Index   PDF

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molpro@molpro.net 2016-05-01