From 6df119aaba815a2f88887c202bdd0799e13457b6 Mon Sep 17 00:00:00 2001
From: Pierre-Francois Loos <pierrefrancois.loos@gmail.com>
Date: Thu, 20 Jul 2023 21:54:31 +0200
Subject: [PATCH] move exchange

---
 src/AOtoMO/exchange_matrix_MO_basis.f90 | 26 +++++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 src/AOtoMO/exchange_matrix_MO_basis.f90

diff --git a/src/AOtoMO/exchange_matrix_MO_basis.f90 b/src/AOtoMO/exchange_matrix_MO_basis.f90
new file mode 100644
index 0000000..5cb13b1
--- /dev/null
+++ b/src/AOtoMO/exchange_matrix_MO_basis.f90
@@ -0,0 +1,26 @@
+subroutine exchange_matrix_MO_basis(nBas,c,P,G,K)
+
+! Compute exchange matrix in the MO basis
+
+  implicit none
+  include 'parameters.h'
+
+! Input variables
+
+  integer,intent(in)            :: nBas
+  double precision,intent(in)   :: c(nBas,nBas),P(nBas,nBas)
+  double precision,intent(in)   :: G(nBas,nBas,nBas,nBas)
+
+! Output variables
+
+  double precision,intent(out)  :: K(nBas,nBas)
+
+! Compute Hartree Hamiltonian in the AO basis
+
+  call exchange_matrix_AO_basis(nBas,P,G,K)
+
+! Transform Coulomb matrix in the MO basis 
+
+  K = matmul(transpose(c),matmul(K,c))
+
+end subroutine exchange_matrix_MO_basis