TURBOMOLE Users Forum

TURBOMOLE Modules => Ricc2 => Topic started by: mhoefli on January 28, 2010, 03:19:14 PM

Title: Discretized Transition Density (from ricc2 excited state calculation)
Post by: mhoefli on January 28, 2010, 03:19:14 PM

Hey Folks,

maybe I missed in the documentation, and it might be not ricc2 specific...

...is there an option to write out the Transition Density between ground and excited state on a grid? Similar to Density=(transition=x) in gaussian. I am interested in using it in the TDC-method from Brent Krueger. http://www.chem.hope.edu/~krieg/TDC/background/tdc_background.htm

The optimal format would be a cube file but I am also happy with converting others.

Best wishes

Martin Hoefling

Title: Re: Discretized Transition Density (from ricc2 excited state calculation)
Post by: christof.haettig on February 10, 2010, 04:12:01 PM

Dear Martin,

because of the non-variational nature of Coupled-Cluster response theory (or equivalently EOM-CC theory) , the excited states
are described by eigenvalues and eigenvectors of the non-hermitian matrix. Therefore left and right eigenvectors are
different and on get different left and right transition moments and left and right transition densities, which don't have
on there one a physical meaning. Only the product of left and right transition moments in related to observable.

In short: the results for CC2 (or any other CC) calculation on transition moments can not be cast into such simple
representation with a single transition density (or you have to make some approximations). This is only possible for variational methods.

Christof