From b66d9e0a907c2bd87547d6016f3d41c8455e8a22 Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Tue, 29 Nov 2022 16:21:47 -0600
Subject: [PATCH] Add check for presence of atomic relaxation data in
 PhotonInteraction

---
 include/openmc/photon.h |  3 +++
 openmc/data/photon.py   |  4 +++-
 src/photon.cpp          | 14 ++++++++++++--
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/include/openmc/photon.h b/include/openmc/photon.h
index 09fb3ba01..9901c8c6d 100644
--- a/include/openmc/photon.h
+++ b/include/openmc/photon.h
@@ -100,6 +100,9 @@ public:
   // Bremsstrahlung scaled DCS
   xt::xtensor<double, 2> dcs_;
 
+  // Whether atomic relaxation data is present
+  bool has_atomic_relaxation_ {false};
+
   // Constant data
   static constexpr int MAX_STACK_SIZE =
     7; //!< maximum possible size of atomic relaxation stack
diff --git a/openmc/data/photon.py b/openmc/data/photon.py
index 48ecc3748..fc5da19eb 100644
--- a/openmc/data/photon.py
+++ b/openmc/data/photon.py
@@ -13,7 +13,7 @@ from scipy.interpolate import CubicSpline
 
 import openmc.checkvalue as cv
 from openmc.mixin import EqualityMixin
-from . import HDF5_VERSION
+from . import HDF5_VERSION, HDF5_VERSION_MAJOR
 from .ace import Table, get_metadata, get_table
 from .data import ATOMIC_SYMBOL, EV_PER_MEV
 from .endf import Evaluation, get_head_record, get_tab1_record, get_list_record
@@ -143,6 +143,8 @@ class AtomicRelaxation(EqualityMixin):
         Dictionary indicating the number of electrons in a subshell when neutral
         (values) for given subshells (keys). The subshells should be given as
         strings, e.g., 'K', 'L1', 'L2', etc.
+    subshells : list
+        List of subshells as strings, e.g. ``['K', 'L1', ...]``
     transitions : pandas.DataFrame
         Dictionary indicating allowed transitions and their probabilities
         (values) for given subshells (keys). The subshells should be given as
diff --git a/src/photon.cpp b/src/photon.cpp
index a500ff2d4..590e0cc9f 100644
--- a/src/photon.cpp
+++ b/src/photon.cpp
@@ -156,8 +156,14 @@ PhotonInteraction::PhotonInteraction(hid_t group)
 
     // Read binding energy and number of electrons
     hid_t tgroup = open_group(rgroup, designator.c_str());
-    read_attribute(tgroup, "binding_energy", shell.binding_energy);
-    read_attribute(tgroup, "num_electrons", shell.n_electrons);
+
+    // Read binding energy energy and number of electrons if atomic relaxation
+    // data is present
+    if (attribute_exists(tgroup, "binding_energy")) {
+      has_atomic_relaxation_ = true;
+      read_attribute(tgroup, "binding_energy", shell.binding_energy);
+      read_attribute(tgroup, "num_electrons", shell.n_electrons);
+    }
 
     // Read subshell cross section
     xt::xtensor<double, 1> xs;
@@ -757,6 +763,10 @@ void PhotonInteraction::pair_production(double alpha, double* E_electron,
 
 void PhotonInteraction::atomic_relaxation(int i_shell, Particle& p) const
 {
+  // Return if no atomic relaxation data is present
+  if (!has_atomic_relaxation_)
+    return;
+
   // Stack for unprocessed holes left by transitioning electrons
   int n_holes = 0;
   array<int, MAX_STACK_SIZE> holes;