diff --git a/qpms/qpms_cdefs.pxd b/qpms/qpms_cdefs.pxd
index fbba8dd..56ac441 100644
--- a/qpms/qpms_cdefs.pxd
+++ b/qpms/qpms_cdefs.pxd
@@ -527,11 +527,11 @@ cdef extern from "scatsystem.h":
     cdouble *qpms_scatsys_build_translation_matrix_e_full(cdouble *target,
             const qpms_scatsys_t *ss, cdouble k, qpms_bessel_t J)
     cdouble *qpms_scatsys_build_modeproblem_matrix_irrep_packed(cdouble *target,
-            const qpms_scatsys_t *ss, qpms_iri_t iri, cdouble k)
+            const qpms_scatsys_t *ss, qpms_iri_t iri, cdouble k) nogil
     cdouble *qpms_scatsys_build_translation_matrix_e_irrep_packed(cdouble *target,
-            const qpms_scatsys_t *ss, qpms_iri_t iri, cdouble k, qpms_bessel_t J)
+            const qpms_scatsys_t *ss, qpms_iri_t iri, cdouble k, qpms_bessel_t J) nogil
     cdouble *qpms_scatsys_build_modeproblem_matrix_irrep_packed_orbitorderR(
-            cdouble *target, const qpms_scatsys_t *ss, qpms_iri_t iri, cdouble k)
+            cdouble *target, const qpms_scatsys_t *ss, qpms_iri_t iri, cdouble k) nogil
     cdouble *qpms_scatsys_build_modeproblem_matrix_irrep_packed_serial(
             cdouble *target, const qpms_scatsys_t *ss, qpms_iri_t iri, cdouble k) nogil
     cdouble *qpms_scatsys_incident_field_vector_full(cdouble *target_full,