Millimeter-wave spectrum of 2-propanimine

Abstract

Up to date, only 6 imines have been detected in the interstellar medium. The 3-carbon imine, 2-propanimine ((CH${}_3$)${}_2$C=NH), is predicted to be the structural isomer with the lowest energy in the C${}_3$H${}_7$N group, and appears to be a good candidate for astronomical searches. Unexpectedly, no microwave or millimeter wave spectrum is available for 2-propanimine. In this work, we provide the first high resolution millimeter wave spectrum of 2-propanimine and its analysis. With the guide of this laboratory measurement, we aim to search for 2-propanimine in two molecule-rich sources Sgr B2(N) and IRAS 16293-2422 using observations from the Atacama Large Millimeter/submillimeter Array (ALMA). Starting from a synthesized sample, we measured the spectrum of 2-propanimine from 50 to 500 GHz, and the ground state lines are successfully assigned and fitted using XIAM and ERHAM programs with the aid of theoretical calculations. The barriers to internal rotation of the two CH${}_3$ tops are determined to be 531.956(64) cm${}^{-1}$ and 465.013(26) cm${}^{-1}$. These data are able to provide reliable prediction of transition frequencies for astronomical search. Although a few line matches exist, no confirmed detection of 2-propanimine has been found in the hot molecular core Sgr B2(N1S) and the Class 0 protostar IRAS 16293B. Upper-limits of its column density have been derived, and indicate that 2-propanimine is at least 18 times less abundant than methanimine in Sgr B2(N1S), and is at most 50-83 % of methanimine in IRAS 16293B.

arXiv comment14 pages, 10 figures

References in corpus (29)

• Trigonometric Parallaxes Of High-Mass Star Forming Regions: Our View Of The Milky Way
• Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M)
• The ALMA Protostellar Interferometric Line Survey (PILS): First results from an unbiased submillimeter wavelength line survey of the Class 0 protostellar binary IRAS 16293-2422 with ALMA
• Detection of amino acetonitrile in Sgr B2(N)
• Exploring Molecular Complexity with ALMA (EMoCA): Deuterated complex organic molecules in Sagittarius B2(N2)
• Weeds: a CLASS extension for the analysis of millimeter and sub-millimeter spectral surveys
• Re-exploring Molecular Complexity with ALMA (ReMoCA): Interstellar detection of urea
• The ALMA-PILS survey: Inventory of complex organic molecules towards IRAS 16293-2422 A
• The ALMA-PILS survey: First detections of ethylene oxide, acetone and propanal toward the low-mass protostar IRAS 16293-2422
• Discovery in space of ethanolamine, the simplest phospholipid head group
• Detection of E-cyanomethanimine towards Sagittarius B2(N) in the Green Bank Telescope PRIMOS Survey
• The Detection of Interstellar Ethanimine (CH3CHNH) from Observations taken during the GBT PRIMOS Survey
• The ALMA-PILS survey: Complex nitriles towards IRAS 16293--2422
• Arcsecond resolution images of the chemical structure of the low-mass protostar IRAS 16293-2422
• The complex chemistry of hot cores in Sagittarius B2(N): Influence of cosmic-ray ionization and thermal history
• Probing the chemical complexity of amines in the ISM: detection of vinylamine (C${}_2$H${}_3$NH${}_2$) and tentative detection of ethylamine (C${}_2$H${}_5$NH${}_2$)
• Propargylimine in the laboratory and in space: millimetre-wave spectroscopy and first detection in the ISM
• Detection of Interstellar Acetone Toward the Orion-KL Hot Core
• The ALMA-PILS survey: Stringent limits on small amines and nitrogen-oxides towards IRAS 16293-2422B
• Chemistry of massive young stellar objects with a disk-like structure
• Methylamine and other simple N-bearing species in the hot cores NGC 6334I MM1-3
• Structure of the hot molecular core G10.47+0.03
• Detection of New Methylamine (CH${}_3$NH${}_2$) Sources: Candidates for Future Glycine Surveys
• Acetone in Orion BN/KL - High-resolution maps of a special oxygen-bearing molecule
• Chemical modeling for predicting the abundances of certain aldimines and amines in hot cores
• The Difference in Abundances between N-bearing and O-bearing Species in High-Mass Star-Forming Regions
• The ALMA-PILS survey: First tentative detection of 3-hydroxypropenal (HOCHCHCHO) in the interstellar medium and chemical modeling of the C${}_3$H${}_4$O${}_2$ isomers
• Complex Organic Molecules at High Spatial Resolution Toward Orion-KL II: Kinematics
• Far-infrared laboratory spectroscopy of aminoacetonitrile and first interstellar detection of its vibrationally excited transitions

Cited by in corpus (1)

• Rotational Spectra and Search for Aromatic Imines: 9-Iminofluorene and Benzophenone imine