diff --git a/src/csf/cfgCI_utils.c b/src/csf/cfgCI_utils.c
index 23b984a0..c11b38dc 100644
--- a/src/csf/cfgCI_utils.c
+++ b/src/csf/cfgCI_utils.c
@@ -68,10 +68,16 @@ void getBFIndexList(int NSOMO, int *BF1, int *IdxListBF1){
                     break;
                 }
             }
-            BFcopy[Iidx] = -1;
-            BFcopy[Jidx] = -1;
-            IdxListBF1[Jidx] = Iidx;
-            IdxListBF1[Iidx] = Jidx;
+            if(countN1 <= 0){
+                BFcopy[Iidx] = -1;
+                IdxListBF1[Iidx] = Iidx;
+            }
+            else{
+                BFcopy[Iidx] = -1;
+                BFcopy[Jidx] = -1;
+                IdxListBF1[Jidx] = Iidx;
+                IdxListBF1[Iidx] = Jidx;
+            }
         }
     }
 
@@ -328,10 +334,21 @@ void convertCSFtoDetBasis(int64_t Isomo, int MS, int rowsmax, int colsmax, doubl
                  Get Overlap
     ************************************/
     // Fill matrix
+
+    int rowsbftodetI, colsbftodetI;
+
+    /***********************************
+         Get BFtoDeterminant Matrix
+    ************************************/
+
+    printf("In convertcsftodet\n");
+    convertBFtoDetBasis(Isomo, MS, &bftodetmatrixI, &rowsbftodetI, &colsbftodetI);
+
     int rowsI = 0;
     int colsI = 0;
 
-    getOverlapMatrix(Isomo, MS, &overlapMatrixI, &rowsI, &colsI, &NSOMO);
+    //getOverlapMatrix(Isomo, MS, &overlapMatrixI, &rowsI, &colsI, &NSOMO);
+    getOverlapMatrix_withDet(bftodetmatrixI, rowsbftodetI, colsbftodetI, Isomo, MS, &overlapMatrixI, &rowsI, &colsI, &NSOMO);
 
 
     /***********************************
@@ -342,14 +359,6 @@ void convertCSFtoDetBasis(int64_t Isomo, int MS, int rowsmax, int colsmax, doubl
 
     gramSchmidt(overlapMatrixI, rowsI, colsI, orthoMatrixI);
 
-    /***********************************
-         Get BFtoDeterminant Matrix
-    ************************************/
-
-    int rowsbftodetI, colsbftodetI;
-
-    convertBFtoDetBasis(Isomo, MS, &bftodetmatrixI, &rowsbftodetI, &colsbftodetI);
-
     /***********************************
          Get Final CSF to Det Matrix
     ************************************/
@@ -1297,12 +1306,16 @@ void getbftodetfunction(Tree *dettree, int NSOMO, int MS, int *BF1, double *rowv
     double fac = 1.0;
     for(int i = 0; i < NSOMO; i++)
         donepq[i] = 0.0;
+    for(int i=0;i<npairs;++i){
+      for(int j=0;j<NSOMO;++j)
+        detslist[i*NSOMO + j]=0;
+    }
 
     for(int i = 0; i < NSOMO; i++){
         idxp = BF1[i];
         idxq = BF1[idxp];
         // Do one pair only once
-        if(donepq[idxp] > 0.0 || donepq[idxq] > 0.0) continue;
+        if(donepq[idxp] > 0.0 || donepq[idxq] > 0.0 || idxp == idxq) continue;
         fac *= 2.0;
         donepq[idxp] = 1.0;
         donepq[idxq] = 1.0;
@@ -1425,6 +1438,11 @@ void convertBFtoDetBasis(int64_t Isomo, int MS, double **bftodetmatrixptr, int *
 
         for(int k=0;k<ndets;k++)
             rowvec[k]=0.0;
+
+        for(int j=0;j<NSOMO;++j){
+          BF1[j]=0;
+          IdxListBF1[j]=0;
+        }
     }
 
     // Garbage collection
diff --git a/src/csf/tree_utils.c b/src/csf/tree_utils.c
index 5336a6da..1266b890 100644
--- a/src/csf/tree_utils.c
+++ b/src/csf/tree_utils.c
@@ -17,27 +17,31 @@ void buildTree(Tree *bftree,
     if(isomo > NSOMOMax || icpl < 0 || izeros > zeromax ) return;
 
     // If we find a valid BF assign its address
-    if(isomo == NSOMOMax){
+    if(isomo == NSOMOMax && icpl == MSmax){
         (*inode)->addr = bftree->rootNode->addr;
         bftree->rootNode->addr += 1;
         return;
     }
 
     // Call 0 branch
-    if(((*inode)->C0) == NULL && izeros+1 <= zeromax){
-        ((*inode)->C0) = malloc(sizeof(Node));
-        (*(*inode)->C0) = (Node){ .C0 = NULL, .C1 = NULL, .PREV = *inode, .addr = -1, .cpl = 0, .iSOMO = isomo };
-        buildTree(bftree, &(*inode)->C0, isomo+1, izeros+1, icpl+1, NSOMOMax, MSmax);
+    if(izeros+1 <= zeromax){
+      if(((*inode)->C0) == NULL){
+          ((*inode)->C0) = malloc(sizeof(Node));
+          (*(*inode)->C0) = (Node){ .C0 = NULL, .C1 = NULL, .PREV = *inode, .addr = -1, .cpl = 0, .iSOMO = isomo };
+          buildTree(bftree, &(*inode)->C0, isomo+1, izeros+1, icpl+1, NSOMOMax, MSmax);
+      }
+      else buildTree(bftree, &(*inode)->C0, isomo+1, izeros+1, icpl+1, NSOMOMax, MSmax);
     }
-    else buildTree(bftree, &(*inode)->C0, isomo+1, izeros+1, icpl+1, NSOMOMax, MSmax);
 
     // Call 1 branch
-    if(((*inode)->C1) == NULL && icpl-1 >= 0){
-        ((*inode)->C1) = malloc(sizeof(Node));
-        (*(*inode)->C1) = (Node){ .C0 = NULL, .C1 = NULL, .PREV = *inode, .addr = -1, .cpl = 1, .iSOMO = isomo };
-        buildTree(bftree, &(*inode)->C1, isomo+1, izeros+0, icpl-1, NSOMOMax, MSmax);
+    if(icpl-1 >=0){
+      if(((*inode)->C1) == NULL){
+          ((*inode)->C1) = malloc(sizeof(Node));
+          (*(*inode)->C1) = (Node){ .C0 = NULL, .C1 = NULL, .PREV = *inode, .addr = -1, .cpl = 1, .iSOMO = isomo };
+          buildTree(bftree, &(*inode)->C1, isomo+1, izeros+0, icpl-1, NSOMOMax, MSmax);
+      }
+      else buildTree(bftree, &(*inode)->C1, isomo+1, izeros+0, icpl-1, NSOMOMax, MSmax);
     }
-    else buildTree(bftree, &(*inode)->C1, isomo+1, izeros+0, icpl-1, NSOMOMax, MSmax);
 
     return;
 }