Update the documentation

PW/Doc/INPUT_PW.def

@@ -1177,13 +1177,15 @@ input_description -distribution {Quantum Espresso} -package PWscf -program pw.x
                 is not configured there.
             }
             info { 
-                Specify @ref lda_plus_u = .TRUE. to enable DFT+U calculations
+                Specify @ref lda_plus_u = .TRUE. to enable DFT+U, DFT+U+V, or 
+                DFT+U+J calculations.
                 See: Anisimov, Zaanen, and Andersen, PRB 44, 943 (1991); 
                      Anisimov et al., PRB 48, 16929 (1993); 
                      Liechtenstein, Anisimov, and Zaanen, PRB 52, R5467 (1994).
-                You must specify, for each species with a U term, the value of
+                You must specify, for each Hubbard atom, the value of
-                U and (optionally) alpha, J of the Hubbard model (all in eV):
+                U and (optionally) V, J, alpha of the Hubbard model (all in eV):
-                see @ref lda_plus_u_kind, @ref Hubbard_U, @ref Hubbard_alpha, @ref Hubbard_J
+                see @ref lda_plus_u_kind, @ref Hubbard_U, @ref Hubbard_V, 
+                @ref Hubbard_J, @ref Hubbard_alpha
             }
         }
         var lda_plus_u_kind -type INTEGER { 
@@ -1240,9 +1242,13 @@ input_description -distribution {Quantum Espresso} -package PWscf -program pw.x
             default { 0.D0 for all species }
             info {
                 Hubbard_alpha(i) is the perturbation (on atom i, in eV)
-                used to compute U with the linear-response method of
+                used to compute U (and V) with the linear-response method of
                 Cococcioni and de Gironcoli, PRB 71, 035105 (2005)
-                (only for @ref lda_plus_u_kind=0)
+                (only for @ref lda_plus_u_kind=0 and 2).
+                Note: Hubbard U and V can be computed using the HP code
+                which is based on density-functional pertubation theory,
+                and it gives exactly the same result as the method of 
+                Cococcioni and de Gironcoli.
             }
         }
         dimension Hubbard_beta -start 1 -end ntyp -type REAL { 
@@ -1251,7 +1257,7 @@ input_description -distribution {Quantum Espresso} -package PWscf -program pw.x
                 Hubbard_beta(i) is the perturbation (on atom i, in eV)
                 used to compute J0 with the linear-response method of
                 Cococcioni and de Gironcoli, PRB 71, 035105 (2005)
-                (only for @ref lda_plus_u_kind=0). See also 
+                (only for @ref lda_plus_u_kind=0 and 2). See also 
                 PRB 84, 115108 (2011).
             }
         }

XSpectra/README

@@ -5,8 +5,7 @@ XSPECTRA : X-ray spectra calculation
 by C. Gougoussis, O. Bunau, A. Seitsonen, F. Mauri and M. Calandra
 
 K 
-The theoretical approach on which XSpectra is based was
+The theoretical approach on which XSpectra is based was described in:
-described in:
 
 L23 edges,
 
@@ -27,9 +26,8 @@ If you use only Norm Conserving pseudopotentials, you should also
 cite the following publication:
 
 M. Taillefumier, D. Cabaret, A. M. Flank, and F. Mauri
-"X-ray absorption near-edge structure calculations with the pseudopotentials: Application to the K edge in diamond and αalpha
+"X-ray absorption near-edge structure calculations with the pseudopotentials: Application to the K edge in diamond 
--quartz"
+and alpha -quartz", Phys. Rev. B 66, 195107 (2002)
-Phys. Rev. B 66, 195107 (2002)
 
 The implementation of the DFT+U approximation and its application to
 K-edge XAS in NiO was performed in:
@@ -37,6 +35,13 @@ K-edge XAS in NiO was performed in:
 C. Gougoussis, M. Calandra, A. Seitsonen, Ch. Brouder, A. Shukla, F. Mauri
 " Intrinsic charge transfer gap in NiO from  Ni K -edge x-ray absorption spectroscopy", Phys. Rev. B 79, 045118 (2009)
 
+The interface of the DFT+U+V code and the XSpectra code and its application to
+oxygen K-edge XAS in LaFeO3 and LaFe0.75Ni0.25O3 is described in:
+
+I. Timrov, P. Agrawal, X. Zhang, S. Erat, R. Liu, A. Braun, M. Cococcioni, M. Calandra, N. Marzari, D. Passerone,
+"Electronic structure of pristine and Ni-substituted LaFeO3 from near edge x-ray absorption fine structure experiments 
+and first-principles simulations", Phys. Rev. Research 2, 033265 (2020)
+
 Finally you should cite properly the Quantum Espresso package.
 
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