[molpro-user] CCSDT(Q) energy calculation using MRCC Kallay on Molpro

Shiblee Ratan shibleeratan at gmail.com
Sat Dec 9 01:54:55 CET 2017

Hello Molpro Experts,

Is it possible to do an *MRCC Kallay CCSDT(Q) energy* calculation for
an *open-shell
ROHF reference*? The error message below keeps giving me hope:

*Executing mrcc... Approximate CC methods are not implemented for standard
ROHF orbitals! Use semicanonical orbitals! Fatal error in mrcc. ? Error ?
Fatal error in mrcc. ? The problem occurs in MRCC*

I am trying to calculate the CCSDT(Q) energy for a (doublet-B1) NH2
molecule. Tried a lot of things, but it seems like there is no option to
force Molpro to generate *semicanonical ROHF orbitals* as the error message
above wants. ROHF keeps generating canonical/standard orbitals in record
file 2100.2.

CCSDT(Q) energy works fine with *UHF reference* though.

Any help or suggestion to make MRCC Kallay's *CCSDT(Q)* work with the *ROHF
reference* will be greatly appreciated.

Input file I used is:

Geometry = {
N  ,  H1  , rNH
H2 ,  N   , rNH  ,  H1  ,  aHNH

rNH   =    1.04100000 Ang
aHNH  =  100.72710000 Degree


*orbital,type=semicanonical or pseudo-canonical*              <--- Tried
these and many other combinations but did not make any difference



*Dr. Shiblee Ratan Barua*
*Postdoctoral Research Fellow*Rm S162, Bld 34
NASA Goddard Space Flight Center
8800 Greenbelt Rd, Greenbelt, MD USA 20771
*Email*: shibleeratan at gmail.com, shiblee.barua at nasa.gov
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.molpro.net/pipermail/molpro-user/attachments/20171208/834e916c/attachment.html>

More information about the Molpro-user mailing list