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Title: ASSIGNMENT OF 5069 A DIFFUSE INTERSTELLAR BAND TO HC{sub 4}H{sup +}: DISAGREEMENT WITH LABORATORY ABSORPTION BAND

Abstract

Krelowski et al. have reported a weak, diffuse interstellar band (DIB) at 5069 A which appears to match in both mid-wavelength and width the A {sup 2}{Pi}{sub u}-X {sup 2}{Pi}{sub g} gas-phase origin absorption band of HC{sub 4}H{sup +}. Here, we present laboratory rotational profiles at low temperatures which are then compared with the 5069 A DIB using {approx}0.1 and 0.3 A line widths based on a realistic line-of-sight interstellar velocity dispersion. Neither the band shape nor the wavelength of the maximum absorption match, which makes the association of the 5069 A DIB with HC{sub 4}H{sup +} unlikely. The magnetic dipole transition X {sup 2}{Pi}{sub g} {Omega} = 1/2{yields}X {sup 2}{Pi}{sub g} {Omega} = 3/2 within the ground electronic state which competes with collisional excitation is also considered. In addition, we present the laboratory gas-phase spectrum of the A {sup 2}{Pi}{sub u}-X {sup 2}{Pi}{sub g} transition of HC{sub 4}H{sup +} measured at 25 K in an ion trap and identify further absorption bands at shorter wavelengths for comparison with future DIB data.

Authors:
; ; ; ;  [1];  [2];  [3]
  1. Department of Chemistry, University of Basel, Klingelbergstr. 80, CH-4056 Basel (Switzerland)
  2. 1234 Hewlett Place, Victoria, BC V8S 4P7 (Canada)
  3. National Research Council of Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada)
Publication Date:
OSTI Identifier:
21560454
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 729; Journal Issue: 2; Other Information: DOI: 10.1088/2041-8205/729/2/L20
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; EXCITATION; GROUND STATES; IONS; M1-TRANSITIONS; TRAPS; CHARGED PARTICLES; ENERGY LEVELS; ENERGY-LEVEL TRANSITIONS; MULTIPOLE TRANSITIONS; SORPTION

Citation Formats

Maier, J. P., Chakrabarty, S., Mazzotti, F. J., Rice, C. A., Dietsche, R., Walker, G. A. H., and Bohlender, D. A., E-mail: j.p.maier@unibas.ch. ASSIGNMENT OF 5069 A DIFFUSE INTERSTELLAR BAND TO HC{sub 4}H{sup +}: DISAGREEMENT WITH LABORATORY ABSORPTION BAND. United States: N. p., 2011. Web. doi:10.1088/2041-8205/729/2/L20.
Maier, J. P., Chakrabarty, S., Mazzotti, F. J., Rice, C. A., Dietsche, R., Walker, G. A. H., & Bohlender, D. A., E-mail: j.p.maier@unibas.ch. ASSIGNMENT OF 5069 A DIFFUSE INTERSTELLAR BAND TO HC{sub 4}H{sup +}: DISAGREEMENT WITH LABORATORY ABSORPTION BAND. United States. doi:10.1088/2041-8205/729/2/L20.
Maier, J. P., Chakrabarty, S., Mazzotti, F. J., Rice, C. A., Dietsche, R., Walker, G. A. H., and Bohlender, D. A., E-mail: j.p.maier@unibas.ch. Thu . "ASSIGNMENT OF 5069 A DIFFUSE INTERSTELLAR BAND TO HC{sub 4}H{sup +}: DISAGREEMENT WITH LABORATORY ABSORPTION BAND". United States. doi:10.1088/2041-8205/729/2/L20.
@article{osti_21560454,
title = {ASSIGNMENT OF 5069 A DIFFUSE INTERSTELLAR BAND TO HC{sub 4}H{sup +}: DISAGREEMENT WITH LABORATORY ABSORPTION BAND},
author = {Maier, J. P. and Chakrabarty, S. and Mazzotti, F. J. and Rice, C. A. and Dietsche, R. and Walker, G. A. H. and Bohlender, D. A., E-mail: j.p.maier@unibas.ch},
abstractNote = {Krelowski et al. have reported a weak, diffuse interstellar band (DIB) at 5069 A which appears to match in both mid-wavelength and width the A {sup 2}{Pi}{sub u}-X {sup 2}{Pi}{sub g} gas-phase origin absorption band of HC{sub 4}H{sup +}. Here, we present laboratory rotational profiles at low temperatures which are then compared with the 5069 A DIB using {approx}0.1 and 0.3 A line widths based on a realistic line-of-sight interstellar velocity dispersion. Neither the band shape nor the wavelength of the maximum absorption match, which makes the association of the 5069 A DIB with HC{sub 4}H{sup +} unlikely. The magnetic dipole transition X {sup 2}{Pi}{sub g} {Omega} = 1/2{yields}X {sup 2}{Pi}{sub g} {Omega} = 3/2 within the ground electronic state which competes with collisional excitation is also considered. In addition, we present the laboratory gas-phase spectrum of the A {sup 2}{Pi}{sub u}-X {sup 2}{Pi}{sub g} transition of HC{sub 4}H{sup +} measured at 25 K in an ion trap and identify further absorption bands at shorter wavelengths for comparison with future DIB data.},
doi = {10.1088/2041-8205/729/2/L20},
journal = {Astrophysical Journal Letters},
number = 2,
volume = 729,
place = {United States},
year = {Thu Mar 10 00:00:00 EST 2011},
month = {Thu Mar 10 00:00:00 EST 2011}
}