Hi Alan,
I have just realized that the CORE option in NATORB seems to be not
working properly in case of MP2 or CCSD. Please do not use that until
the problem is fixed.
I would however recommend to always include core orbitals in the natural
orbital calculations. When they are frozen in the correlated
calculation, the natural orbitals and the canonical orbitals are
identical with occupation number 2 in the case of using nonrelaxed
density matrices. The presence of them in the natural orbital
calculation does not affect any other natural orbitals. By using the
relaxed density matrices, it is important to include the frozen core
orbitals in the natural orbital calculation, as their occupation number
is not 2 anymore.
To print all natural orbitals, one should use the maximum number of
virtual (external) orbitals in any irrep. In the given example, that
would be PRINT=26, but you can give any larger number, too. For example
PRINT=100.
Regards,
Werner.
On 14.03.2017 18:37, Alan Chien wrote:
> I'm toying with CCSD natural orbitals for butadiene as a starting point
> for higher level calculations. Full input included at the end.
>
> {ccsd;
> expec,type=norelax;
> dm,2141.2;
> natorb,record=2141.2,print=23,_core_=0;
> }
>
> I'm confused as to the function of "_core_". The manual
> (https://www.molpro.net/info/2015.1/doc/manual/node341.html#sec:natorb_mp2
> <https://www.molpro.net/info/2015.1/doc/manual/node341.html#sec:natorb_mp2>)
> states that core=1 freezes the core orbitals when constructing the
> density matrix.
>
> If I'm already using the frozen-core approximation in my CCSD
> calculation, which I am, why does setting core=1 change my NO occupancy
> results? The core orbitals should not be coupled to the rest of the
> orbitals at all in a non-relaxed density matrix, so it should not matter
> if the core orbitals are included or not in the density matrix.
>
> Any insight appreciated,
> Alan Chien
>
>
>
> _Input below_
> _
> _
> ***,buta
> geometry={
> C 0.6009903066 -0.4020172170 0.0000000000
> C -0.6009903066 0.4020172170 0.0000000000
> C 1.8329498097 0.1103686968 0.0000000000
> C -1.8329498097 -0.1103686968 0.0000000000
> H 1.9876059086 1.1777308428 0.0000000000
> H -1.9876059086 -1.1777308428 0.0000000000
> H 0.4702284110 -1.4752930006 0.0000000000
> H -0.4702284110 1.4752930006 0.0000000000
> H 2.7040838288 -0.5215644347 0.0000000000
> H -2.7040838288 0.5215644347 0.0000000000
> }
> basis=roos(3s2p1d/2s1p) !anos-l-pvdz
> {hf;
> orbprint,5;
> }
> {ccsd;
> expec,type=norelax;
> dm,2141.2;
> natorb,record=2141.2,print=23,core=0;
> }
> {put,molden,ccsd.molden;
> orbital,record=2141.2,type=natural
> }
>
>
>
>
>
>
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