TY - JOUR
T1 - Chemical Dynamics Simulations of Intermolecular Energy Transfer
T2 - Azulene + N2 Collisions
AU - Kim, Hyunsik
AU - Paul, Amit K.
AU - Pratihar, Subha
AU - Hase, William L.
N1 - Funding Information:
The research reported here is based upon work supported by the Air Force Office of Scientific Research, BRI Grant No. FA 9550-12-1-0443, and the Robert A. Welch Foundation under Grant No. D-0005. Support was also provided by the High Performance Computing Center at Texas Tech Univ, under the direction of P. W. Smith. Parts of the computations were also performed on Robinson, a general computer cluster of the Dept. of Chemistry and Biochemistry, Texas Tech Univ, purchased by the NSF CRIF-MU Grant No. CHE-0840493.
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/7/14
Y1 - 2016/7/14
N2 - Chemical dynamics simulations were performed to investigate collisional energy transfer from highly vibrationally excited azulene in a N2 bath. The intermolecular potential between Az and N2, used for the simulations, was determined from MP2/6-31+G∗ ab initio calculations. Az∗ is prepared with an 87.5 kcal/mol excitation energy by using quantum microcanonical sampling, including its 95.7 kcal/mol zero-point energy. The average energy of Az∗ versus time, obtained from the simulations, shows different rates of Az∗ deactivation depending on the N2 bath density. Using the N2 bath density and Lennard-Jones collision number, the average energy transfer per collision 〈δEc〉 was obtained for Az∗ as it is collisionally relaxed. By comparing 〈δEc〉 versus the bath density, the single collision limiting density was found for energy transfer. The resulting 〈δEc〉, for an 87.5 kcal/mol excitation energy, is 0.30 ± 0.01 and 0.32 ± 0.01 kcal/mol for harmonic and anharmonic Az potentials, respectively. For comparison, the experimental value is 0.57 ± 0.11 kcal/mol. During Az∗ relaxation there is no appreciable energy transfer to Az translation and rotation, and the energy transfer is to the N2 bath.
AB - Chemical dynamics simulations were performed to investigate collisional energy transfer from highly vibrationally excited azulene in a N2 bath. The intermolecular potential between Az and N2, used for the simulations, was determined from MP2/6-31+G∗ ab initio calculations. Az∗ is prepared with an 87.5 kcal/mol excitation energy by using quantum microcanonical sampling, including its 95.7 kcal/mol zero-point energy. The average energy of Az∗ versus time, obtained from the simulations, shows different rates of Az∗ deactivation depending on the N2 bath density. Using the N2 bath density and Lennard-Jones collision number, the average energy transfer per collision 〈δEc〉 was obtained for Az∗ as it is collisionally relaxed. By comparing 〈δEc〉 versus the bath density, the single collision limiting density was found for energy transfer. The resulting 〈δEc〉, for an 87.5 kcal/mol excitation energy, is 0.30 ± 0.01 and 0.32 ± 0.01 kcal/mol for harmonic and anharmonic Az potentials, respectively. For comparison, the experimental value is 0.57 ± 0.11 kcal/mol. During Az∗ relaxation there is no appreciable energy transfer to Az translation and rotation, and the energy transfer is to the N2 bath.
UR - http://www.scopus.com/inward/record.url?scp=84978658465&partnerID=8YFLogxK
U2 - 10.1021/acs.jpca.6b00893
DO - 10.1021/acs.jpca.6b00893
M3 - Article
AN - SCOPUS:84978658465
VL - 120
SP - 5187
EP - 5196
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
SN - 1089-5639
IS - 27
ER -