diff --git a/docs/user_guide/4.3ADMPQeqForce.md b/docs/user_guide/4.3ADMPQeqForce.md
index d48cb4417..9c9812ffc 100644
--- a/docs/user_guide/4.3ADMPQeqForce.md
+++ b/docs/user_guide/4.3ADMPQeqForce.md
@@ -21,7 +21,7 @@ The total coulombic energy is composed of the followling four parts.
 Here, the first term $`E_{pc}`$ is electrostatic energy of point-charge systems, which is typically done in Ewald/PME method. For isolated molecule/clusters, it can also be  computed using cutoff scheme:
 
 ```math
-E_{pc}\left(q_i\right) = \sum_{i<j}\frac{q_i q_j}{r_{ij}}
+E_{pc}\left(q_i\right) = \sum_{i< j}\frac{q_i q_j}{r_{ij}}
 ```
 Note that we currently only consider Ewad3D (so called Ewald3DC method), instead of rigorous Ewald2D.
 
@@ -32,7 +32,7 @@ The second term is the short-range damping term, which can be different for diff
 * For example, for EQeq model (`JPCL 3, 2506`), the damping kernel is ($`K`$ is the dielectric constant):
 
 ```math
-E_{sr}\left(q_i\right) = \sum_{i<j} f(r_{ij})\frac{q_i q_j}{r_{ij}} \\
+E_{sr}\left(q_i\right) = \sum_{i< j} f(r_{ij})\frac{q_i q_j}{r_{ij}} \\
 f(r) = - \exp\left[-\left(\frac{J_{ij}r}{K}\right)^2\right]\left(1-\frac{J_{ij}r}{K}+\left(\frac{J_{ij}r}{K}\right)^2\right) \\
 J_{ij} = \sqrt{J_i J_j}
 ```