Quantum-mechanical Rotational and Vibrational Signatures of
Astrophyscially relevant Gas-Phase Stereo-isomeric Species of Leucine
Abstract
The search for life-supporting molecules in outer space is an ever
growing endeavour. Towards this, the quantum-mechanical computations
supporting the astronomical spectroscopic observations are becoming
valuable tools to unravel the complex chemical network in the
interstellar medium (ISM). In the present work, quantum-mechanical
computations are performed to obtain the rotational and vibrational
line-data of gas-phase conformers of amino acid Leucine and its isomeric
species predicted to be involved in its stereoinversion under the
conditions of ISM. These species exhibit diverse chemistry including
branched skeleton and zwitterionic ammonium ylides. Notably, the present
work employs vibrational second order perturbation theory to account for
anharmonic effects in rotational and vibrational transitions. The
spectroscopic data computed in this work can assist in the detection of
Leucine and its isomeric species in different regions of ISM.