### TPA Relative Photon Polarizations

Posted:

**07 Apr 2020, 00:05**Hello, when calculating two photon cross sections, I get mostly what I need in terms of cross sections and energies. But, it yields a result for linear and circular polarizations. I have looked, but cannot find an answer on whether or not the linear polarization is where the two photons are parallel or perpendicularly polarized relative to each other. Below is my input file and a summarized output.

**DALTON INPUT

.PARALLEL

.RUN RESPONSE

**WAVE FUNCTIONS

.DFT

B3LYP

**RESPONSE

.MAXRM

500

*QUADRATIC

.TWO-PHOTON

.ROOTS

15 0 0 0

**END OF INPUT

+-----------------------------------+

| Two-photon absorption summary |

+-----------------------------------+

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

Sym No Energy Polarization Df Dg D sigma R

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

1 1 5.54 Linear 0.667E-14 0.642E-14 0.390E-13 0.879E-15 0.65

1 1 5.54 Circular 0.667E-14 0.642E-14 0.252E-13 0.568E-15 0.65

Thank you for your time.

**DALTON INPUT

.PARALLEL

.RUN RESPONSE

**WAVE FUNCTIONS

.DFT

B3LYP

**RESPONSE

.MAXRM

500

*QUADRATIC

.TWO-PHOTON

.ROOTS

15 0 0 0

**END OF INPUT

+-----------------------------------+

| Two-photon absorption summary |

+-----------------------------------+

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

Sym No Energy Polarization Df Dg D sigma R

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

1 1 5.54 Linear 0.667E-14 0.642E-14 0.390E-13 0.879E-15 0.65

1 1 5.54 Circular 0.667E-14 0.642E-14 0.252E-13 0.568E-15 0.65

Thank you for your time.