make a heading smaller

Author: arm61

_build/classical_methods/van_der_waals.md

@@ -12,7 +12,7 @@ next_page:
 comment: "***PROGRAMMATICALLY GENERATED, DO NOT EDIT. SEE ORIGINAL FILES IN /content***"
 ---
 
-### The van der Waals interaction
+## The van der Waals interaction
 
 The potential model for the short-range interaction between atoms is less well defined.
 It is often referred to as the **van der Waals** interaction, and encompasses both the attractive London dispersion effects and the repulsive Pauli exclusion principle. 

content/classical_methods/van_der_waals.ipynb

@@ -4,7 +4,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "### The van der Waals interaction\n",
+    "## The van der Waals interaction\n",
     "\n",
     "The potential model for the short-range interaction between atoms is less well defined.\n",
     "It is often referred to as the **van der Waals** interaction, and encompasses both the attractive London dispersion effects and the repulsive Pauli exclusion principle. \n",