TY  - JOUR
AU  - Hadidi, Rim
AU  - Božanić, Dušan K.
AU  - Ganjitabar, Hassan
AU  - Garcia, Gustavo A.
AU  - Powis, Ivan
AU  - Nahon, Laurent
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9814
AB  - Proline is a unique amino-acid, with a secondary amine fixed within a pyrrolidine ring providing specific structural properties to proline-rich biopolymers. Gas-phase proline possesses four main H-bond stabilized conformers differing by the ring puckering and carboxylic acid orientation. The latter defines two classes of conformation, whose large ionization energy difference allows a unique conformer-class tagging via electron spectroscopy. Photoelectron circular dichroism (PECD) is an intense chiroptical effect sensitive to molecular structures, hence theorized to be highly conformation-dependent. Here, we present experimental evidence of an intense and striking conformer-specific PECD, measured in the vacuum ultraviolet (VUV) photoionization of proline, as well as a conformer-dependent cation fragmentation behavior. This finding, combined with theoretical modeling, allows a refinement of the conformational landscape and energetic ordering, that proves inaccessible to current molecular electronic structure calculations. Additionally, astrochemical implications regarding a possible link of PECD to the origin of life’s homochirality are considered in terms of plausible temperature constraints.
T2  - Communications Chemistry
T1  - Conformer-dependent vacuum ultraviolet photodynamics and chiral asymmetries in pure enantiomers of gas phase proline
VL  - 4
IS  - 1
SP  - 1
EP  - 14
DO  - 10.1038/s42004-021-00508-z
ER  - 

@article{
author = "Hadidi, Rim and Božanić, Dušan K. and Ganjitabar, Hassan and Garcia, Gustavo A. and Powis, Ivan and Nahon, Laurent",
year = "2021",
abstract = "Proline is a unique amino-acid, with a secondary amine fixed within a pyrrolidine ring providing specific structural properties to proline-rich biopolymers. Gas-phase proline possesses four main H-bond stabilized conformers differing by the ring puckering and carboxylic acid orientation. The latter defines two classes of conformation, whose large ionization energy difference allows a unique conformer-class tagging via electron spectroscopy. Photoelectron circular dichroism (PECD) is an intense chiroptical effect sensitive to molecular structures, hence theorized to be highly conformation-dependent. Here, we present experimental evidence of an intense and striking conformer-specific PECD, measured in the vacuum ultraviolet (VUV) photoionization of proline, as well as a conformer-dependent cation fragmentation behavior. This finding, combined with theoretical modeling, allows a refinement of the conformational landscape and energetic ordering, that proves inaccessible to current molecular electronic structure calculations. Additionally, astrochemical implications regarding a possible link of PECD to the origin of life’s homochirality are considered in terms of plausible temperature constraints.",
journal = "Communications Chemistry",
title = "Conformer-dependent vacuum ultraviolet photodynamics and chiral asymmetries in pure enantiomers of gas phase proline",
volume = "4",
number = "1",
pages = "1-14",
doi = "10.1038/s42004-021-00508-z"
}

Hadidi, R., Božanić, D. K., Ganjitabar, H., Garcia, G. A., Powis, I.,& Nahon, L.. (2021). Conformer-dependent vacuum ultraviolet photodynamics and chiral asymmetries in pure enantiomers of gas phase proline. in Communications Chemistry, 4(1), 1-14.
https://doi.org/10.1038/s42004-021-00508-z

Hadidi R, Božanić DK, Ganjitabar H, Garcia GA, Powis I, Nahon L. Conformer-dependent vacuum ultraviolet photodynamics and chiral asymmetries in pure enantiomers of gas phase proline. in Communications Chemistry. 2021;4(1):1-14.
doi:10.1038/s42004-021-00508-z .

Hadidi, Rim, Božanić, Dušan K., Ganjitabar, Hassan, Garcia, Gustavo A., Powis, Ivan, Nahon, Laurent, "Conformer-dependent vacuum ultraviolet photodynamics and chiral asymmetries in pure enantiomers of gas phase proline" in Communications Chemistry, 4, no. 1 (2021):1-14,
https://doi.org/10.1038/s42004-021-00508-z . .

TY  - JOUR
AU  - Hadidi, Rim
AU  - Božanić, Dušan K.
AU  - Garcia, Gustavo A.
AU  - Nahon, Laurent
PY  - 2018
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7998
AB  - Photoelectron circular dichroism (PECD) is an intense orbital-specific chiroptical effect observed as asymmetries in the angular distribution of photoelectrons produced by photoionization of randomly oriented pure enantiomers with circularly polarized light. After a broad introduction placing this effect in the context of new physical chiral-sensitive methods, we review the main characteristics of PECD in terms of molecular photoionization dynamics. We stress also the analytical capabilities of PECD to retrieve enantiomeric excesses (e.es.) and to probe subtle details of the whole molecular potential, some of them exemplified by the showcase camphor and fenchone molecules. We then present the case of the amino acid alanine for which an interplay between PECD and conformer population is rationalized. Based on this study, we propose a photophysical astrophysical scenario for the origin of life's homochirality, relying upon the asymmetry of the associated recoiling alanine parent ion that could lead at the relevant Lyman- energy to an e.e. of up to 4% in a given line of sight, which appears independent of the temperature. In an attempt to generalize this scenario to other amino acids, new data on proline showing an e.e. of 12%, of the same sign as alanine, are also presented.Abbreviations ARPES: Angle-resolved photoemission; CMS-Xa: Continuum multiple scattering with Xa local-exchange potential; CPL: Circularly polarized light; CD: Circular dichroism; CSM: Circumstellar medium; DPI: Dissociative ionization; HHG: High harmonics generation; HOMO: Highest occupied molecular orbital; ISM: Interstellar medium; KE: Kinetic energy; MS: Mass spectrometry; MW: Microwave; PAD: Photoelectron angular distribution; PECD: Photoelectron circular dichroism; PECD-PICO: Photoelectron circular dichroism / photoion coincidence; PEPICO: Photoelectron / photoion coincidence; PES: Photoelectron spectrum; PV: Parity Violation; REMPI: Resonance-enhanced multi-photon ionization; RH: Resistive heating; TD: Thermodesorption; UV: Ultra-violet; VMI: Velocity map imaging; VUV: Vacuum ultra-violet.
T2  - Advances in Physics: X
T1  - Electron asymmetries in the photoionization of chiral molecules: possible astrophysical implications
VL  - 3
IS  - 1
SP  - 1477530
DO  - 10.1080/23746149.2018.1477530
ER  - 

@article{
author = "Hadidi, Rim and Božanić, Dušan K. and Garcia, Gustavo A. and Nahon, Laurent",
year = "2018",
abstract = "Photoelectron circular dichroism (PECD) is an intense orbital-specific chiroptical effect observed as asymmetries in the angular distribution of photoelectrons produced by photoionization of randomly oriented pure enantiomers with circularly polarized light. After a broad introduction placing this effect in the context of new physical chiral-sensitive methods, we review the main characteristics of PECD in terms of molecular photoionization dynamics. We stress also the analytical capabilities of PECD to retrieve enantiomeric excesses (e.es.) and to probe subtle details of the whole molecular potential, some of them exemplified by the showcase camphor and fenchone molecules. We then present the case of the amino acid alanine for which an interplay between PECD and conformer population is rationalized. Based on this study, we propose a photophysical astrophysical scenario for the origin of life's homochirality, relying upon the asymmetry of the associated recoiling alanine parent ion that could lead at the relevant Lyman- energy to an e.e. of up to 4% in a given line of sight, which appears independent of the temperature. In an attempt to generalize this scenario to other amino acids, new data on proline showing an e.e. of 12%, of the same sign as alanine, are also presented.Abbreviations ARPES: Angle-resolved photoemission; CMS-Xa: Continuum multiple scattering with Xa local-exchange potential; CPL: Circularly polarized light; CD: Circular dichroism; CSM: Circumstellar medium; DPI: Dissociative ionization; HHG: High harmonics generation; HOMO: Highest occupied molecular orbital; ISM: Interstellar medium; KE: Kinetic energy; MS: Mass spectrometry; MW: Microwave; PAD: Photoelectron angular distribution; PECD: Photoelectron circular dichroism; PECD-PICO: Photoelectron circular dichroism / photoion coincidence; PEPICO: Photoelectron / photoion coincidence; PES: Photoelectron spectrum; PV: Parity Violation; REMPI: Resonance-enhanced multi-photon ionization; RH: Resistive heating; TD: Thermodesorption; UV: Ultra-violet; VMI: Velocity map imaging; VUV: Vacuum ultra-violet.",
journal = "Advances in Physics: X",
title = "Electron asymmetries in the photoionization of chiral molecules: possible astrophysical implications",
volume = "3",
number = "1",
pages = "1477530",
doi = "10.1080/23746149.2018.1477530"
}

Hadidi, R., Božanić, D. K., Garcia, G. A.,& Nahon, L.. (2018). Electron asymmetries in the photoionization of chiral molecules: possible astrophysical implications. in Advances in Physics: X, 3(1), 1477530.
https://doi.org/10.1080/23746149.2018.1477530

Hadidi R, Božanić DK, Garcia GA, Nahon L. Electron asymmetries in the photoionization of chiral molecules: possible astrophysical implications. in Advances in Physics: X. 2018;3(1):1477530.
doi:10.1080/23746149.2018.1477530 .

Hadidi, Rim, Božanić, Dušan K., Garcia, Gustavo A., Nahon, Laurent, "Electron asymmetries in the photoionization of chiral molecules: possible astrophysical implications" in Advances in Physics: X, 3, no. 1 (2018):1477530,
https://doi.org/10.1080/23746149.2018.1477530 . .