add global_formula, heating_furnace_name, and precursor_powders to the schema

Author: minhsueh

mpcontribs-lux/mpcontribs/lux/projects/alab/schemas/experiments.py

@@ -44,7 +44,24 @@ class Experiment(BaseModel, extra="forbid"):
         default=None, description="Experiment subgroup (e.g., NSC_249, Na_123)"
     )
 
-    target_formula: str = Field(description="Target chemical formula")
+    target_formula: str | None = Field(
+        default=None,
+        description=(
+            "The formula used internally to determine precursor weights. "
+            "May differ from the true intended formula (global_formula) due to experimental "
+            "constraints (e.g. oxygen mass balancing corrections, excess "
+            "alkali for battery materials). Not always a chemically meaningful "
+            "representation of what was attempted."
+        ),
+    )
+
+    global_formula: str | None = Field(
+        default=None,
+        description=(
+            "The canonical formula for the target material, independent of per-run precursor adjustments. "
+            "Represents what the experiment was ultimately trying to synthesize."
+        ),
+    )
 
     last_updated: datetime = Field(description="Last modification timestamp")
 
@@ -56,6 +73,11 @@ class Experiment(BaseModel, extra="forbid"):
         default=None, description="Optional notes about the experiment"
     )
 
+    precursor_powders: list[str] | None = Field(
+        default=None,
+        description="List of precursor powder names used in the experiment"
+    )
+
     # === Heating fields (prefix: heating_) ===
     heating_method: Literal["standard", "atmosphere", "manual", "none"] | None = Field(
         default=None, description="Heating method used"
@@ -85,6 +107,10 @@ class Experiment(BaseModel, extra="forbid"):
         default=None, description="Whether low temperature calcination was used"
     )
 
+    heating_furnace_name: str | None = Field(
+        default=None, description="Heating furnace type"
+    )
+
     # === Recovery fields (prefix: recovery_) ===
     recovery_total_dosed_mass_mg: float | None = Field(
         default=None, description="Total mass of all powders dosed in mg"