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CATEGORIES:Theory - Chemistry Research Interest Group
SUMMARY:Holomorphic Hartree-Fock Theory: Exploiting Multip
le SCF Solutions for Non-Orthogonal Configuration
Interaction - Hugh Burton
DTSTART;TZID=Europe/London:20171011T144000
DTEND;TZID=Europe/London:20171011T150000
UID:TALK84071AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/84071
DESCRIPTION:Although it is the lowest energy Hartree-Fock stat
e that is usually most sought after\, the non-line
ar self-consistent field (SCF) equations also admi
t a number of higher energy solutions that have be
en shown to resemble excited molecular states. Mot
ivated by this\, these states can be used as a bas
is set for Non-Orthogonal Configuration Interactio
n (NOCI) to obtain adiabatic states which show sim
ilar properties to the results of more expensive c
orrelation techniques. However\, the existence of
an SCF state across all molecular geometries is no
t guaranteed and there are many known examples of
coalescing solutions. The disappearance of a Hartr
ee-Fock state severely hinders NOCI by leading to
a sudden change in the basis set size\, resulting
in discontinuous energy curves. In holomorphic Har
tree-Fock theory\, a holomorphic analogue of the H
artree-Fock equations is constructed by removing t
he complex conjugation of orbital coefficients fro
m the energy functional. By making this alteration
\, SCF states that usually disappear as the molecu
lar geometry is changed are instead found to exten
d into the complex plane\, allowing a continuous b
asis to be constructed for NOCI. In this talk\, I
present the theoretical and mathematical foundatio
ns of holomorphic Hartree-Fock theory and demonstr
ate its contribution to NOCI calculations.
LOCATION:Department of Chemistry\, Cambridge\, Unilever lec
ture theatre
CONTACT:Lisa Masters
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