working slurm script, seems brittle

CADES/VASP/vasp_job.slurm

-#!/bin/bash
-#PBS -S /bin/bash
-#PBS -m be
-#PBS -M youremail@ornl.gov
-#PBS -N sample_job
-#PBS -q batch
-#PBS -l nodes=2:ppn=32:hw32
-#PBS -l walltime=00:30:00
-#PBS -l naccesspolicy=singlejob
-#PBS -A cnms
-#PBS -W group_list=cades-cnms
-#PBS -l qos=std
+#!/bin/bash -l
+#SBATCH -J test2 
+#SBATCH --nodes 2
+#SBATCH --ntasks-per-node 32
+#SBATCH --cpus-per-task 1
+#SBATCH --exclusive
+#SBATCH --mem=100g
+#SBATCH -p batch
+#SBATCH -A cnms 
+#SBATCH -t 00:30:00
+
+#VASP runs including significant communication especially for SCALAPACK run
+#slower than they should.  Refrain from using more than ~1 cpu per atom
+#past 64 or 128 cores LSCALAPACK=.FALSE.
+module purge
+module load env/cades-cnms
+module load vasp/5.4.4_opt
 
 export OMP_NUM_THREADS=1
+echo $SLURM_JOB_NODELIST
 
-cd $PBS_O_WORKDIR
+echo `ldd $VASP`
 
-#this can be useful to see from outside shells
-cat $PBS_NODEFILE >pbs_nodefile
+SLURM_CPU_BIND=VERBOSE
 
+MACHINEFILE="nodes.$SLURM_JOB_ID"
+srun -l /bin/hostname | sort -n | awk '{print $2}' | sed -e 's/.ornl.gov//' > $MACHINEFILE
 
-#VASP runs including significant communication especially for SCALAPACK run
-#slower than they should.  Refrain from using more than ~1 cpu per atom
-#past 64 or 128 cores LSCALAPACK=.FALSE.
-module load env/cades-cnms
-module load vasp/5.4.1
+echo $SLURM_NTASKS
 
-mpirun -v --report-bindings ${VASP_MPI_FLAGS} $VASP 2>&1 >vasp_out
+mpirun -hostfile $MACHINEFILE -v --report-bindings ${VASP_MPI_FLAGS} $VASP 2>&1 >vasp_out