# PolarThis
method keyword requests that the dipole electric field polarizabilities (and hyperpolarizabilities,
if possible) be computed. No geometry change or derivatives are implied, but this
keyword may be combined in the same job with numerical differentiation of forces
by specifying both **Freq** and **Polar** in the
route section. **Freq** and **Polar**
may *not* be combined for methods lacking analytic gradients (MP4(SDTQ),
QCISD(T), CCSD(T), BD, and so on). Note that **Polar** is done by default when
second derivatives are computed analytically. Normally, polarizabilities
and hyperpolarizabilities are computed using static frequencies. However, frequency-dependent
polarizabilities and hyperpolarizabilities [220,221,222,224,225]
may be computed by including **CPHF=RdFreq** in the
route section and specifying the desired frequency in the input file. Optical
rotations [261,262,263,264,265,266,550,551,552,553]
may also be predicted via the **OptRot **option [223,267,268,269,270,271,305,554]. **OptRot**
Perform optical rotation calculation.
**DCSHG** Do extra frequency-dependent
CPHF for dc-SHG (direct current second harmonic generation) hyperpolarizabilities.
This option implies **CPHF=RdFreq** as well.
**Step=***N*
Specifies the step size in the electric field to be 0.0001*N* atomic units.
**Analytic**
Analytically compute the polarizability and, if possible, the hyperpolarizability.
This is possible for RHF and UHF and MP2 for which it is the default. The polarizability
is always computed during analytic frequency calculations.
**Cubic**
Numerically differentiate analytic polarizabilities to produce hyperpolarizabilities.
**Numerical**
Computes the polarizability as a numerical derivative of the dipole moment (itself
the analytic derivative of the energy, of course, not the expectation value in
the case of MP2 or CI energies). The default for methods for which only analytic
first derivatives are available.
**EnOnly** Requests double numerical
differentiation of energies to produce polarizabilities. **EnergyOnly**, a
synonym for **EnOnly**, is a misnomer, since analytic first derivatives will
also be differentiated twice, to produce hyperpolarizabilities, when they are
available.
**Restart** Restarts a *numerical* polarizability
calculation from the checkpoint file. A failed **Polar** calculation may be
restarted from its checkpoint file by simply repeating the route section of the
original job, adding the **Restart** option to the **Polar** keyword. No
other input is required.
**Dipole** Compute the dipole polarizabilities
(this is the default).
Polarizabilities
and hyperpolarizabilities will be automatically computed for HF and MP2. **Polar**
will compute polarizabilities only, and **Polar=EnOnly** will produce both
polarizabilities and hyperpolarizabilities for CIS, MP2, MP3, MP4(SDQ), CID, CISD,
CCD, CCSD, QCISD, CASSCF and DFT methods. Polar will produce only polarizabilities
for all other methods (for which no analytic derivatives are available, making
**EnOnly** the default). Note that **Polar** is not available for any semi-empirical
method. **Freq
****CPHF=RdFreq**
**Frequency-Dependent
Properties.** The following job will compute frequency-dependent polarizabilities and
hyperpolarizabilities using ω=0.1 Hartrees:
# Polar CPHF=RdFreq HF/6-31G(d)
Frequency-dependent calculation: w=0.1*
**Molecule specification*
0.1
Performing a frequency-dependent **Polar **calculation results in
the results for the specified frequency following those for the static
case within the output. For example, here are the polarizability values
for a frequency-dependent job (ω=0.1 Hartree):
SCF Polarizabilityfor W= 0.000000:
1 2 3
1 0.482729D+01
2 0.000000D+00 0.112001D+02
3 0.000000D+00 0.000000D+00 0.165696D+02
Isotropic polarizability for W= 0.000000 10.87 Bohr**3
SCF Polarizability for W= 0.100000:
1 2 3
1 0.491893D+01
2 0.000000D+00 0.115663D+02
3 0.000000D+00 0.000000D+00 0.171826D+02
Isotropic polarizability for W= 0.100000 11.22 Bohr**3.
A static polarizability calculation would include only
the first section. Similar output follows for hyperpolarizabilities and additional
properties. **Optical Rotations. **Here is the key part of the output
for optical rotations jobs (**OptRot** option). In this case, we have performed
a frequency-dependant calculation by including **CPHF=RdFreq**
in the route section and specified a frequency of 500 nm:
w= 0.000000 a.u., Optical Rotation Beta= 1.2384 au.
Molar Mass = 74.4103 grams/mole,[Alpha]D = 643.30 deg.
G' tensor for W= 0.091127:
-27.88112715 8.27183975 58.48555729
-7.74920313 9.64293589 28.50024234
-14.62301919 4.52918305 10.26760578
w= 0.091127 a.u., Optical Rotation Beta= 2.6569 au.
Molar Mass = 74.4103 grams/mole, **[Alpha] ( 5000.0 A) = 1917.10 deg.**
The static results are listed first in the output
(ω=0.0), followed by those for the specified frequency. The specific rotation
value is highlighted in the output. |