[molpro-user] hessian always calculated numerically for root=2 ump2, rccsd, rccsd(t) geometry opts

[Benj FitzPatrick]

Hello,
I am trying to find transition states for a couple of open shell systems with
2006.1 (patch level 34).  When it gets to the first OPT where it calculates the
hessian I get differing results based on which level of theory I use.  If I use
uhf/rhf/mcscf the hessian is computed using analytic gradients it it makes 9
calculations.  For ump2, rccsd, and rccsd(t) it wants to do 90 calculations to
get the hessian.  To me this looks like it is trying to use finite differences.
 This only happens when I'm looking at a transition state, if I use root=1 the
behavior of ump2, etc. is the same as uhf.  Is this behavior expected?  If no,
why is molpro doing this and is it possible to get around this?  I included an
input file below.
Thanks,
Benj FitzPatrick
University of Chicago

 ***,ump2 irc of c3h5o going from the epoxide to o having the radical ***
 memory,50,M;
B1=1.07
B2=1.09
B3=1.3
B4=1.10
A1=115
A2=125
A3=130
D1=170
D2=0
geometry
ang;
nosym;
 C;
 H, 1,   B1;
 H, 1,   B2,    2,   A1;
 C, 1,   B3,    3,   A2,    2,   D1;
 H, 4,   B4,    1,   A3,    3,   D2;
end

 basis=avdz;
{uhf;
 wf,15,1,1}
{ump2;
 wf,15,1,1}
{optg,root=2}