diff --git a/docs/source/run/parameters.rst b/docs/source/run/parameters.rst
index d642bebe53..3565d6a637 100644
--- a/docs/source/run/parameters.rst
+++ b/docs/source/run/parameters.rst
@@ -18,15 +18,17 @@ in the input script with ``my_constants``.
 
 Thereby, the following constants are predefined:
 
-============ =================== ================= ====================
-**variable** **name**            **SI value**      **normalized value**
-q_e          elementary charge   1.602176634e-19   1
-m_e          electron mass       9.1093837015e-31  1
-m_p          proton mass         1.67262192369e-27 1836.15267343
-epsilon0     vacuum permittivity 8.8541878128e-12  1
-mu0          vacuum permeability 1.25663706212e-06 1
-clight       speed of light      299'792'458.      1
-============ =================== ================= ====================
+============ ========================= =====================
+**variable** **name**                  **Value**
+q_e          elementary charge         1.602176634e-19
+m_e          electron mass             9.1093837015e-31
+m_p          proton mass               1.67262192369e-27
+epsilon0     vacuum permittivity       8.8541878128e-12
+mu0          vacuum permeability       1.25663706212e-06
+clight       speed of light            299'792'458.
+hbar         reduced Planck constant   1.054571817e-34
+r_e          classical electron radius 2.817940326204929e-15
+============ ========================= =====================
 
 For a list of supported functions see the
 `AMReX documentation <https://amrex-codes.github.io/amrex/docs_html/Basics.html#parser>`__.
diff --git a/src/Hipace.cpp b/src/Hipace.cpp
index 99d77bc65d..9cf7edbf6e 100644
--- a/src/Hipace.cpp
+++ b/src/Hipace.cpp
@@ -49,7 +49,7 @@ Hipace_early_init::Hipace_early_init (Hipace* instance)
     } else {
         m_phys_const = make_constants_SI();
     }
-    Parser::addConstantsToParser(m_phys_const);
+    Parser::addConstantsToParser();
     Parser::replaceAmrexParamsWithParser();
 
     queryWithParser(pph, "depos_order_xy", m_depos_order_xy);
diff --git a/src/utils/Parser.H b/src/utils/Parser.H
index 2333e1326a..26f0ac5e84 100755
--- a/src/utils/Parser.H
+++ b/src/utils/Parser.H
@@ -38,18 +38,17 @@ namespace Parser
     // {"true", 1},
     // {"false", 0}
 
-    /** \brief add Physical constants to Parser constants
-     *
-     * \param[in] phys_const the constants to add
-     */
+    /** \brief add Physical constants to Parser constants */
     inline void
-    addConstantsToParser (const PhysConst& phys_const) {
-        hipace_constants.insert({"clight", phys_const.c});
-        hipace_constants.insert({"epsilon0", phys_const.ep0});
-        hipace_constants.insert({"mu0", phys_const.mu0});
-        hipace_constants.insert({"q_e", phys_const.q_e});
-        hipace_constants.insert({"m_e", phys_const.m_e});
-        hipace_constants.insert({"m_p", phys_const.m_p});
+    addConstantsToParser () {
+        hipace_constants.insert({"clight",   PhysConstSI::c   });
+        hipace_constants.insert({"epsilon0", PhysConstSI::ep0 });
+        hipace_constants.insert({"mu0",      PhysConstSI::mu0 });
+        hipace_constants.insert({"q_e",      PhysConstSI::q_e });
+        hipace_constants.insert({"m_e",      PhysConstSI::m_e });
+        hipace_constants.insert({"m_p",      PhysConstSI::m_p });
+        hipace_constants.insert({"hbar",     PhysConstSI::hbar});
+        hipace_constants.insert({"r_e",      PhysConstSI::r_e});
     }
 
     /** \brief replace ParmParse input with a Parsed version