From 4fff7c9fd2adab865c0fee03b5e358b02cc163aa Mon Sep 17 00:00:00 2001 From: Hugh Burton Date: Mon, 30 Nov 2020 21:34:39 +0000 Subject: [PATCH] minor edits --- Manuscript/EPAWTFT.tex | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/Manuscript/EPAWTFT.tex b/Manuscript/EPAWTFT.tex index 9845ad9..1878208 100644 --- a/Manuscript/EPAWTFT.tex +++ b/Manuscript/EPAWTFT.tex @@ -1295,11 +1295,11 @@ orbitals [see Eq.~\eqref{eq:RHF_orbs}] with $\theta_{\alpha}^{\text{RHF}} = \the %\begin{equation} % E_\text{HF}(0, 0) = \frac{1}{2} (2 U - 4 \epsilon). %\end{equation} -With this representation, the parametrised RMP Hamiltonian becomes +With this representation, the parametrised \hugh{atomic} RMP Hamiltonian becomes \begin{widetext} \begin{equation} \label{eq:H_RMP} -\bH_\text{RMP}\qty(\lambda) = +\hugh{\bH_\text{atom}\qty(\lambda)} = \begin{pmatrix} 2(U-\epsilon) - \lambda U & -\lambda t & -\lambda t & 0 \\ -\lambda t & (U-\epsilon) - \lambda U & 0 & -\lambda t \\ @@ -1337,7 +1337,8 @@ In contrast, smaller $\epsilon$ gives a weaker attraction to the atomic site, representing strong screening of the nuclear attraction by core and valence electrons, and again a less negative $\lambda$ is required for ionisation to occur. Both of these factors are common in atoms on the right-hand side of the periodic table, \eg\ \ce{F}, -\ce{O}, \ce{Ne}, and thus molecules containing these atoms are often class $\beta$ systems with +\ce{O}, \ce{Ne}. +Molecules containing these atoms are therefore often class $\beta$ systems with a divergent RMP series due to the MP critical point. \cite{Goodson_2004,Sergeev_2006} % EXACT VERSUS APPROXIMATE @@ -1384,10 +1385,9 @@ For $\lambda>1$, the HF potential becomes an attractive component in Stillinger' Hamiltonian displayed in Eq.~\eqref{eq:HamiltonianStillinger}, while the explicit electron-electron interaction becomes increasingly repulsive. Critical points along the positive real $\lambda$ axis for closed-shell molecules then represent -points where the two-electron repulsion overcomes the attractive HF potential and an electron -are successively expelled from the molecule.\cite{Sergeev_2006} +points where the two-electron repulsion overcomes the attractive HF potential and a single electron dissociates from the molecule.\cite{Sergeev_2006} -Symmetry-breaking in the UMP reference creates different HF potentials for the spin-up and spin-down electrons. +In contrast, symmetry-breaking in the UMP reference creates different HF potentials for the spin-up and spin-down electrons. Consider the reference UHF solution where the spin-up and spin-down electrons are localised on the left and right sites respectively. The spin-up HF potential will then be a repulsive interaction from the spin-down electron @@ -1413,7 +1413,7 @@ occurs exactly at $\lambda = 1$. In this limit, the ground-state EPs approach the real axis (Fig.~\ref{subfig:ump_ep_to_cp}) and the avoided crossing creates a gradient discontinuity in the ground-state energy (dashed lines in Fig.~\ref{subfig:ump_cp}). We therefore find that, in the strong correlation limit, the symmetry-broken ground-state EP becomes -a new type of MP critical and represents a QPT in the perturbation approximation. +a new type of MP critical point and represents a QPT in the perturbation approximation. Furthermore, this argument explains why the dominant UMP singularity lies so close, but always outside, the radius of convergence (see Fig.~\ref{fig:RadConv}).