From 1999c39ab4e517cbd82b587dd9181f7a0b1d56a1 Mon Sep 17 00:00:00 2001
From: Philipp Rehner <prehner@ethz.ch>
Date: Thu, 11 Dec 2025 17:08:29 +0100
Subject: [PATCH] Fix in the calculation of enthalpies of adsorption for
 mixtures

---
 CHANGELOG.md                                      |  1 +
 crates/feos-core/src/phase_equilibria/tp_flash.rs | 12 ++++++------
 crates/feos-dft/src/adsorption/pore.rs            |  6 +++---
 crates/feos-dft/src/profile/properties.rs         |  2 +-
 4 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3d921692f..f1eb78c74 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 ### Fixed
+- Fixed calculation of enthalpies of adsorption for mixtures. [#329](https://github.com/feos-org/feos/pull/329)
 - Updated to `ndarray` 0.17 and `num-dual`0.13 to fix a broken dependency resolution. [#327](https://github.com/feos-org/feos/pull/327)
 - Fixed calculation of parameter combination in entropy scaling for mixtures in `viscosity_correlation`, `diffusion_correlation`, `thermal_conductivity_correlation`. [#323](https://github.com/feos-org/feos/pull/323)
 
diff --git a/crates/feos-core/src/phase_equilibria/tp_flash.rs b/crates/feos-core/src/phase_equilibria/tp_flash.rs
index 0a5ca1c6e..1c9c3072a 100644
--- a/crates/feos-core/src/phase_equilibria/tp_flash.rs
+++ b/crates/feos-core/src/phase_equilibria/tp_flash.rs
@@ -90,10 +90,10 @@ impl<E: Residual> State<E> {
         log_iter!(verbosity, "{:-<77}", "");
         log_iter!(
             verbosity,
-            " {:4} |                | {:10.8} | {:10.8}",
+            " {:4} |                | {:10.8?} | {:10.8?}",
             0,
-            new_vle_state.vapor().molefracs,
-            new_vle_state.liquid().molefracs,
+            new_vle_state.vapor().molefracs.data.as_vec(),
+            new_vle_state.liquid().molefracs.data.as_vec(),
         );
 
         let mut iter = 0;
@@ -279,11 +279,11 @@ impl<E: Residual> PhaseEquilibrium<E, 2> {
             let res = res_vec.norm();
             log_iter!(
                 verbosity,
-                " {:4} | {:14.8e} | {:.8} | {:.8}",
+                " {:4} | {:14.8e} | {:.8?} | {:.8?}",
                 iter,
                 res,
-                self.vapor().molefracs,
-                self.liquid().molefracs,
+                self.vapor().molefracs.data.as_vec(),
+                self.liquid().molefracs.data.as_vec(),
             );
             if res < abs_tol {
                 return Ok(true);
diff --git a/crates/feos-dft/src/adsorption/pore.rs b/crates/feos-dft/src/adsorption/pore.rs
index 64446d350..c7602b7d5 100644
--- a/crates/feos-dft/src/adsorption/pore.rs
+++ b/crates/feos-dft/src/adsorption/pore.rs
@@ -139,9 +139,9 @@ where
     }
 
     pub fn enthalpy_of_adsorption(&self) -> FeosResult<MolarEnergy> {
-        Ok((self.partial_molar_enthalpy_of_adsorption()?
-            * Dimensionless::new(&self.profile.bulk.molefracs))
-        .sum())
+        Ok(self
+            .partial_molar_enthalpy_of_adsorption()?
+            .dot(&Dimensionless::new(self.profile.bulk.molefracs.clone())))
     }
 
     fn _henry_coefficients<N: DualNum<f64> + Copy + DctNum>(&self, temperature: N) -> DVector<N> {
diff --git a/crates/feos-dft/src/profile/properties.rs b/crates/feos-dft/src/profile/properties.rs
index 5501e8c24..225967409 100644
--- a/crates/feos-dft/src/profile/properties.rs
+++ b/crates/feos-dft/src/profile/properties.rs
@@ -352,7 +352,7 @@ where
         let n = drho_dmu.shape()[0];
         let mut dn_dmu = DMatrix::zeros(n, n);
         dn_dmu
-            .row_iter_mut()
+            .column_iter_mut()
             .zip(drho_dmu.outer_iter())
             .for_each(|(mut dn, drho)| dn.add_assign(&self.integrate_reduced_segments(&drho)));
         Ok(DnDmu::from_reduced(dn_dmu))