#### WFN

Write a PROAIMS wavefunction (.wfn) file. The name for the created file is read from the input stream, on a separate line. PSI is a synonym for WFN.

#### WFX

Write a wavefunction file used by the newer versions of AIMPAC (.wfx files). The name for the created file is read from the input stream, on a separate line. WfnX is a synonym for WFX.

#### GIAOCx

Include GIAO Cx in .wfn or .wfx file.

#### CSGTCx

Include CSGT Cx in .wfn or .wfx file.

#### Pickett

Write g tensors and other tensors for hyperfine spectra [Curl65, Hirota85, Mills93, Hirota94, Gauss96, Neese01] to the output file in the form of input for Pickett's program [Pickett91] (see spec.jpl.nasa.gov). The following tensors can be computed by Gaussian [Barone94, Minichino94, Barone95, Barone96, Rega96, Cossi03]:

- Nuclear electric quadrupole constants: all jobs
- Rotational constants: Freq=(VibRot[,Anharmonic])
- Quartic centrifugal distortion terms: Freq=(VCD,Anharmonic)
- Electronic spin rotation terms: NMR
- Nuclear spin rotation terms: NMR
- Dipolar hyperfine terms: all jobs
- Fermi contact terms: all jobs

#### SpinRotation

Synonym for NMR Output=Pickett. Includes all hyperfine tensors which can be computed without doing a vibrational frequency calculation.

#### RotationalConstants

Synonym for Freq=VibRot Output=Pickett. Includes almost all hyperfine tensors which can be computed while performing only a harmonic vibrational frequency calculation.

For HF and DFT, you can combine the two preceding options. Output=(RotatationalConstants, SpinRotation) includes all the tensors computable with no more than second derivatives. It is equivalent to Freq=(VCD,VibRot) Output=Pickett.

#### QuarticCentrifugal

Synonym for Freq=(VibRot,Anharm) Output=Pickett. Includes quartic rotation-vibration coupling, but does not include spin-rotation tensors which must be computed separately.

#### ReadAtoms

Read a list of the atoms to include in the input for Pickett’s program (note that this program only accepts tensors for eight nuclei). Atoms numbers are specified in free format, and this input section is blank-terminated. By default, eight interesting atoms are selected automatically by the program.

### Gaussian Interfacing-Related Options

#### MatrixElement

Requests that a text data file for interfacing to other programs be generated. RawMatrixElement requests a binary matrix element file be generated. See Interfacing to Gaussian 16 for details.

#### I4Labels

When combined with the MatrixElement option, use Integer*4 values rather than the current Gaussian integer size when writing the matrix element file.

#### MO2ElectronIntegrals

When combined with the MatrixElement option, include 2 electron integrals over MOs when writing the matrix element file.

#### DerivativeDensities

When combined with the MatrixElement option, include derivative densities from CPHF when writing the matrix element file.

#### GIAOInts

When combined with the MatrixElement option, include GIAO L/R**3 and d2H/dBdm one-electron integral derivatives when writing the matrix element file.