# Asymmetric Top Orbital Transition Moment

This is in principle the interaction of the magnetic moment of
the
electron spin with an external magnetic field:

g_{S}μ_{B}B.S

but is expressed as a tensor to allow for residual orbital
angular
momentum. It is typically written in spherical tensor notation as:

g_{S}μ_{B}B.S - μ_{B}B.Σ_{k=0..2}(-1)^{k}((2k+1)/3)^{½}T^{1}(g_{l}^{k},S)

The default has g_{Saa}
= g_{Sbb} = g_{Scc} = g_{S} =
2.0023193043622, which corresponds to the first term in this
expression. All the parameters have units of Bohr magnetons.

## Parameters

gsaa |
g_{S}^{aa};
Default
is 2.0023193043622 Bohr magnetons |

gsbb |
g_{S}^{bb};_{ }Default
is 2.0023193043622 Bohr magnetons |

gscc |
g_{S}^{cc};_{ }Default
is 2.0023193043622 Bohr magnetons |

gsabbar |
½(g_{S}^{ab}
+ g_{S}^{ba}); Default
is 0 Bohr magnetons. |

gsacbar |
½(g_{S}^{ac}
+ g_{S}^{ca}); Default
is 0 Bohr magnetons. |

gsbcbar |
½(g_{S}^{bc}
+ g_{S}^{cb}); Default
is 0 Bohr magnetons. |

gsamb |
g_{S}^{ab} - g_{S}^{ba}; Default is 0 Bohr
magnetons. |

gsamc |
g_{S}^{ac} - g_{S}^{ca}; Default is 0 Bohr
magnetons. |

gsbmc |
g_{S}^{bc} - g_{S}^{cb}; Default is 0 Bohr
magnetons. |