diff --git a/src/function/Matheval.cpp b/src/function/Matheval.cpp
index 4dacdcd41e3646dca41bab57fec1f04a9f56572b..431067c4b48188590f39f35919edc6d9f884a902 100644
--- a/src/function/Matheval.cpp
+++ b/src/function/Matheval.cpp
@@ -29,7 +29,7 @@ using namespace std;
 namespace PLMD {
 namespace function {
 
-static std::map<string, double> leptonConstants= {
+const static std::map<string, double> leptonConstants= {
   {"e", std::exp(1.0)},
   {"log2e", 1.0/std::log(2.0)},
   {"log10e", 1.0/std::log(10.0)},
diff --git a/src/tools/SwitchingFunction.cpp b/src/tools/SwitchingFunction.cpp
index 5e39ab131ee5001215ceab0e1c30eb9bccf0d253..27e391972b3573167df439d7718b3cd5d54604dd 100644
--- a/src/tools/SwitchingFunction.cpp
+++ b/src/tools/SwitchingFunction.cpp
@@ -29,7 +29,7 @@
 using namespace std;
 namespace PLMD {
 
-static std::map<string, double> leptonConstants= {
+const static std::map<string, double> leptonConstants= {
   {"e", std::exp(1.0)},
   {"log2e", 1.0/std::log(2.0)},
   {"log10e", 1.0/std::log(10.0)},
diff --git a/src/tools/Tools.cpp b/src/tools/Tools.cpp
index 25901cb783d2919eb031d0f127e0f6f64c6a897d..b4853b41c6acaaeb986f5b66ef6f39450e996870 100644
--- a/src/tools/Tools.cpp
+++ b/src/tools/Tools.cpp
@@ -35,7 +35,7 @@
 using namespace std;
 namespace PLMD {
 
-static std::map<string, double> leptonConstants= {
+const static std::map<string, double> leptonConstants= {
   {"e", std::exp(1.0)},
   {"log2e", 1.0/std::log(2.0)},
   {"log10e", 1.0/std::log(10.0)},
diff --git a/src/ves/BF_Custom.cpp b/src/ves/BF_Custom.cpp
index 27bb2662391c791346295b8d33d659a84039e7b9..c6d315126ec9ab17f9d1546ef66285fa2453506d 100644
--- a/src/ves/BF_Custom.cpp
+++ b/src/ves/BF_Custom.cpp
@@ -29,7 +29,7 @@
 namespace PLMD {
 namespace ves {
 
-static std::map<std::string, double> leptonConstants= {
+const static std::map<std::string, double> leptonConstants= {
   {"e", std::exp(1.0)},
   {"log2e", 1.0/std::log(2.0)},
   {"log10e", 1.0/std::log(10.0)},
diff --git a/src/ves/TD_Custom.cpp b/src/ves/TD_Custom.cpp
index c64b7d0259435389237d58a082c42a46b8c72799..c7a24eb4cae8427031bf90dfc95e9244ed4a3d0c 100644
--- a/src/ves/TD_Custom.cpp
+++ b/src/ves/TD_Custom.cpp
@@ -32,7 +32,7 @@
 namespace PLMD {
 namespace ves {
 
-static std::map<std::string, double> leptonConstants= {
+const static std::map<std::string, double> leptonConstants= {
   {"e", std::exp(1.0)},
   {"log2e", 1.0/std::log(2.0)},
   {"log10e", 1.0/std::log(10.0)},