diff --git a/include/ufo/solver.hpp b/include/ufo/solver.hpp
index 169c71a..d598ed6 100644
--- a/include/ufo/solver.hpp
+++ b/include/ufo/solver.hpp
@@ -104,23 +104,32 @@ namespace ufo
         return output;
       }
 
-      class Hdf5File
+      class Hdf5file
       {
         public:
-          inline Hdf5File(std::string filename) : File_(filename, HighFive::File::ReadWrite
-            | HighFive::File::Create | HighFive::File::Truncate) {}
-          template <typename T> inline Hdf5File& read(T& object, std::string name)
+          inline Hdf5file& open_for_read(std::string filename)
           {
-            object = File_.getDataSet(name).read<std::remove_cvref_t<decltype(object)>>();
+            File_ = HighFive::File(filename, HighFive::File::ReadOnly);
             return *this;
           }
-          template <typename T> inline Hdf5File& write(const T& object, std::string name)
+          inline Hdf5file& open_for_write(std::string filename)
           {
-            File_.createDataSet(name, object);
+            File_ = HighFive::File(filename, HighFive::File::ReadWrite | HighFive::File::Create
+              | HighFive::File::Truncate);
+            return *this;
+          }
+          template <typename T> inline Hdf5file& read(T& object, std::string name)
+          {
+            object = File_->getDataSet(name).read<std::remove_cvref_t<decltype(object)>>();
+            return *this;
+          }
+          template <typename T> inline Hdf5file& write(const T& object, std::string name)
+          {
+            File_->createDataSet(name, object);
             return *this;
           }
         protected:
-          HighFive::File File_;
+          std::optional<HighFive::File> File_;
       };
   };
 }
diff --git a/src/plot.cpp b/src/plot.cpp
index 81bd3a9..c0ec7b4 100644
--- a/src/plot.cpp
+++ b/src/plot.cpp
@@ -60,7 +60,7 @@ namespace ufo
     {
       std::vector resolution{ Resolution.first, Resolution.second };
       std::vector range{ Range.first, Range.second };
-      Hdf5File(filename).write(Values, "Values")
+      Hdf5file{}.open_for_write(filename).write(Values, "Values")
         .write(XTicks, "XTicks")
         .write(YTicks, "YTicks")
         .write(resolution, "Resolution")
diff --git a/src/unfold.cpp b/src/unfold.cpp
index 920933a..c0bbc13 100644
--- a/src/unfold.cpp
+++ b/src/unfold.cpp
@@ -26,11 +26,7 @@ namespace ufo
         PrimativeCellBasisNumber(i) = node["PrimativeCellBasisNumber"][i].as<int>();
 
       if (auto value = node["SelectedAtoms"])
-      {
-        SelectedAtoms.emplace();
-        for (unsigned i = 0; i < value.size(); i++)
-          (*SelectedAtoms)[i] = value[i].as<unsigned>();
-      }
+        SelectedAtoms.emplace(value.as<std::vector<unsigned>>());
 
       auto read_file_config = [filename](YAML::Node source, InputOutputFile& config)
       {
@@ -142,7 +138,7 @@ namespace ufo
     {
       std::vector<std::vector<std::vector<double>>> frequency, path;
       std::vector<std::vector<std::vector<std::vector<PhonopyComplex>>>> eigenvector_vector;
-      Hdf5File(QpointDataInputFile.FileName).read(frequency, "/frequency")
+      Hdf5file{}.open_for_read(QpointDataInputFile.FileName).read(frequency, "/frequency")
         .read(eigenvector_vector, "/eigenvector")
         .read(path, "/path");
       std::vector size = { frequency.size(), frequency[0].size(), frequency[0][0].size() };
@@ -262,7 +258,7 @@ namespace ufo
           Weight.back().push_back(mode.Weight);
         }
       }
-      Hdf5File(filename).write(Qpoint, "/Qpoint")
+      Hdf5file{}.open_for_write(filename).write(Qpoint, "/Qpoint")
         .write(Source, "/Source")
         .write(Frequency, "/Frequency")
         .write(Weight, "/Weight");