TY - JOUR
T1 - Isotope shifts and band progressions in SO2 rovibrational energy levels
T2 - using quantum theory to extract rotational constants
AU - Kumar, Praveen
AU - Poirier, Bill
N1 - Funding Information:
This work was largely supported by a research grant (NNX13AJ49G-EXO) from NASA Astrobiology, together with both a research grant (CHE-1665370) and a CRIF MU instrumentation grant (CHE-0840493) from the National Science Foundation (NSF). The Robert A. Welch Foundation (D-1523) is also acknowledged. The authors also acknowledge NASA collaborators Millard Alexander, Hua Guo, and Amy Mullin, for many useful discussions. BP also acknowledges support from the Max-Planck-Institut f?r Physik komplexer Systeme (MPIPKS) Guest Scientist Program. Calculations presented in this paper were performed using the ScalIT suite of parallel codes.
Funding Information:
This work was largely supported by a research grant (NNX13AJ 49G-EXO) from NASA Astrobiology , together with both a research grant (CHE-1665370) and a CRIF MU instrumentation grant (CHE-0840493) from the National Science Foundation (NSF) . The Robert A. Welch Foundation (D-1523) is also acknowledged.
Funding Information:
The authors also acknowledge NASA collaborators Millard Alexander, Hua Guo, and Amy Mullin, for many useful discussions. BP also acknowledges support from the Max-Planck-Institut für Physik komplexer Systeme (MPIPKS) Guest Scientist Program. Calculations presented in this paper were performed using the ScalIT suite of parallel codes.
Publisher Copyright:
© 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.
PY - 2019/9/17
Y1 - 2019/9/17
N2 - We report the isotope shifts of the rotational constants and vibrational band progressions of the sulfur dioxide molecule (SO2), for all four stable sulfur isotopes32S,33S,34S, and36S. These are extracted from exact quantum theoretical calculations of the SO2 rovibrational energy levels, as reported in Chem. Phys.450–451, 59 (2015) and Chem. Phys.461, 34 (2015) and by fitting these levels to a J-shifting (JS)-type scheme, applied to a representative set of total angular momentum (J) values. The approach used to obtain the rotational constants is unusual in that it is derived directly from the quantum theoretical framework used for the earlier calculation, which gives rise to a flexible (i.e., vibrational- and rotational-state-dependent) but symmetric rotor description. The usual (Ka, Kc) rotational quantum numbers are thus replaced with a single body-fixed azimuthal rotation quantum number, K, with various strategies introduced a posteriori to address rotor asymmetry. The new model fits the numerically computed rovibrational levels well, over a fairly broad range of vibrational (v) and rotational (J) excitations. The computed rotational constants agree well with previously reported experimental values [J. Chem. Phys.58, 265 (1973)]. The explicitly v- and J-dependent approach used here should thus prove valuable in broader contexts—e.g., for an analysis of self-shielding in sulfur mass-independent fractionation, even though the rovibrational levels themselves exhibit mass-dependent fractionation.
AB - We report the isotope shifts of the rotational constants and vibrational band progressions of the sulfur dioxide molecule (SO2), for all four stable sulfur isotopes32S,33S,34S, and36S. These are extracted from exact quantum theoretical calculations of the SO2 rovibrational energy levels, as reported in Chem. Phys.450–451, 59 (2015) and Chem. Phys.461, 34 (2015) and by fitting these levels to a J-shifting (JS)-type scheme, applied to a representative set of total angular momentum (J) values. The approach used to obtain the rotational constants is unusual in that it is derived directly from the quantum theoretical framework used for the earlier calculation, which gives rise to a flexible (i.e., vibrational- and rotational-state-dependent) but symmetric rotor description. The usual (Ka, Kc) rotational quantum numbers are thus replaced with a single body-fixed azimuthal rotation quantum number, K, with various strategies introduced a posteriori to address rotor asymmetry. The new model fits the numerically computed rovibrational levels well, over a fairly broad range of vibrational (v) and rotational (J) excitations. The computed rotational constants agree well with previously reported experimental values [J. Chem. Phys.58, 265 (1973)]. The explicitly v- and J-dependent approach used here should thus prove valuable in broader contexts—e.g., for an analysis of self-shielding in sulfur mass-independent fractionation, even though the rovibrational levels themselves exhibit mass-dependent fractionation.
KW - J-shifting
KW - Mass-independent fractionation
KW - Rotational constant
KW - SO isotopologue
KW - Self-shielding
UR - http://www.scopus.com/inward/record.url?scp=85060053980&partnerID=8YFLogxK
U2 - 10.1080/00268976.2019.1567850
DO - 10.1080/00268976.2019.1567850
M3 - Article
AN - SCOPUS:85060053980
VL - 117
SP - 2456
EP - 2469
JO - Molecular Physics
JF - Molecular Physics
SN - 0026-8976
IS - 18
ER -