TY - JOUR

T1 - A prochiral precursor in space? Accurate laboratory characterization of acetylacetylene in the cm-wave region

AU - Lengsfeld, Kevin G.

AU - Buschmann, Philipp

AU - Dohrmann, Frederike

AU - Grabow, Jens -Uwe

N1 - Funding Information: The authors thank the Land Niedersachsen and the Deutsche Forschungsgemeinschaft for funds. K.G.L. gratefully acknowledges the Fonds der Chemischen Industrie for a Ph.D. fellowship.

PY - 2021/3

Y1 - 2021/3

N2 - The most prominent pure rotational transitions of the prochiral, possibly prebiotic molecule acetylacetylene are recorded in the frequency range of 6.5–26.5 GHz for a reliable spectral characterization prerequisite to a possible extraterrestrial observation. Therefore, three different approaches for global fitting of the vibrational ground state are applied to analyze the experimentally determined transition frequencies using the programs SPFIT, XIAM and ERHAM corresponding to different theoretical treatments solving the internal rotation problem. Furthermore, the resulting internal rotation parameter V 3 is compared to those other substituted acetyl species, and derivatives of butynes and possible explanations for the observed trends are given. For the substituted acetyl species, the spectra of acetylfluoride, -chloride, -bromide and -iodide are reanalyzed. The obtained rotational constants have been interpreted in terms of characterizing the geometric structure. A correlation between the tunneling parameter ε 1 and V 3 of several molecular species displaying spectral internal rotation splitting patterns has been found and quantified. This relationship can simplify the analysis of vibrational ground state rotational spectra in finding a suitable starting point for the fitting procedure using the program ERHAM, which is the predestined choice to analyze and predict signal positions up to very high quantum numbers. Being able to predict those signal positions is crucial for a possible comprehensive astronomical identification and subsequent application as an astrophysical probe for the conditions in interstellar molecular clouds.

AB - The most prominent pure rotational transitions of the prochiral, possibly prebiotic molecule acetylacetylene are recorded in the frequency range of 6.5–26.5 GHz for a reliable spectral characterization prerequisite to a possible extraterrestrial observation. Therefore, three different approaches for global fitting of the vibrational ground state are applied to analyze the experimentally determined transition frequencies using the programs SPFIT, XIAM and ERHAM corresponding to different theoretical treatments solving the internal rotation problem. Furthermore, the resulting internal rotation parameter V 3 is compared to those other substituted acetyl species, and derivatives of butynes and possible explanations for the observed trends are given. For the substituted acetyl species, the spectra of acetylfluoride, -chloride, -bromide and -iodide are reanalyzed. The obtained rotational constants have been interpreted in terms of characterizing the geometric structure. A correlation between the tunneling parameter ε 1 and V 3 of several molecular species displaying spectral internal rotation splitting patterns has been found and quantified. This relationship can simplify the analysis of vibrational ground state rotational spectra in finding a suitable starting point for the fitting procedure using the program ERHAM, which is the predestined choice to analyze and predict signal positions up to very high quantum numbers. Being able to predict those signal positions is crucial for a possible comprehensive astronomical identification and subsequent application as an astrophysical probe for the conditions in interstellar molecular clouds.

KW - Acetylacetylene

KW - Acetylhalides

KW - High resolution rotational spectroscopy

KW - Internal rotation

KW - Prebiotics

KW - Tunneling parameter

UR - http://www.scopus.com/inward/record.url?scp=85102647339&partnerID=8YFLogxK

U2 - 10.1016/j.jms.2021.111441

DO - 10.1016/j.jms.2021.111441

M3 - Article

VL - 377

JO - Journal of molecular spectroscopy

JF - Journal of molecular spectroscopy

SN - 0022-2852

M1 - 111441

ER -