Un-catalyzed peptide bond formation between two monomers of glycine, alanine, serine, threonine, and aspartic acid in gas phase: a density functional theory studySnehasis Bhunia, Ajeet Singh and Animesh K. OjhaEur. Phys. J. D, 70 5 (2016) 106DOI: https://doi.org/10.1140/epjd/e2016-60609-8