Our work is at the interface of atomic and molecular (AM) physics with astrophysics. Accurate and complete AM data are required to facilitate reliable interpretation and modeling of astronomical observations. With the rapid advances in space- and ground-based telescope technology, the need for accurate AM data will only become more crucial. Using state-of-the-art quantum-mechanical techniques, we compute atomic and molecular data (cross sections, rate coefficients, transition probabilities, . . .) needed for the modeling of various astronomical environments. We either work closely with other theoretical astrophysicists to utilize this data in their models or we develop our own models.
Our AM physics program includes the investigation of charge transfer due to ion-atom and ion-molecule collisions, formation of diatomic molecules by radiative association, and photodissociation of diatomic molecules. We are involved in a large project to compute a comprehensive set of total and state-selective charge transfer data for use in astrophysical modeling. This data will be made available to the scientific user community via the WWW. We are now extending our program to include formation and destruction of polyatomic molecules, molecular line lists, and rovibrational (de)excitation due to neutral particle collisions.
Our research efforts in astrophysics have been primarily focused on the early Universe. Using the most recently available AM data, some computed by our group, we have investigated the formation of atoms and molecules in the recombination era. We have just began a new project to extend this work to the formation of the very first cosmological objects, i.e., primordial stars and galaxies, with an emphasis on the role of primordial molecules. We are also interested in other astrophysical and atmospheric environments including brown dwarfs, x-ray emission for Jupiter and comets, extrasolar giant planets, supernova ejecta, stellar atmospheres, and the interstellar medium.
G. Shen, P. C. Stancil, J. Wang, J. McCann, and B. M. McLaughlin, “Radiative charge transfer in cold and ultracold Sulphur collisions,” J. Phys. B, submitted (Dec. 19, 2014).
D. B. Henley, R. L. Shelton, R. S. Cumbee, and P. C. Stancil, “XMM-Newton measurement of the galactic halo X-ray emission using a compact shadowing cloud,” Astrophys. J., in press (2015); arXiv:1411.5017
B. H. Yang, P. Zhang, X. Wang, P. C. Stancil, J. M. Bowman, N. Balakrishnan, and R. C. Forrey, “Quantum dynamics of CO-H2 in full dimensionality,” Nature Communications, in press (2015).
K. M. Walker, B. H. Yang, P. C. Stancil, N. Balakrishnan, and R. C. Forrey, “On the Validity of Collider-Mass Scaling for Molecular Rotational Excitation,” Astrophys. J.790, 96 (2014).
R. S. Cumbee, D. B. Henley, P. C. Stancil, R. L. Shelton, J. L. Nolte, Y. Wu, and D. R. Schultz, “Can Charge Exchange Explain Anomalous Soft X-ray Emission in the Cygnus Loop?”, Astrophys. J. Lett. 787, L31 (2014).
D. G. A. Smith, K. Patkowski, D. Trinh, N. Balakrishnan, T.-G. Lee, R. C. Forrey, B. H. Yang, and P. C. Stancil, “Highly correlated electronic structure calculations of the He-C3 van der Waals complex and collision induced rotational transitions of C3,” J. Phys. Chem. A 118, 6351 (2014).
A. Bohr, S. Paolini, R. C. Forrey, N. Balakrishnan, and P. C. Stancil, “A full-dimensional quantum dynamics study of H2+H2 collisions: coupled-states versus close-coupling formulation,” J. Chem. Phys. 140, 064308 (2014).
B. Yang and P. C. Stancil, “Rotational deexcitation of HCl due to He collisions,” Astrophys. J. 783, 92 (2014).
V. K. Veeraghattam, K. Manrodt, S. P. Lewis, and P. C. Stancil, ``The sticking of atomic hydrogen on amorphous water ice," Astrophys. J. 790, 4 (2014).
Stancil B. Yang, P. C. Stancil, N. Balakrishnan, R. C. Forrey, and J. M. Bowman, “Quantum Calculation of Inelastic CO Collisions with H:. I. rotational quenching of low-lying rotational levels”, Astrophys. J. 771, 49 (2013); arXiv: 1305.2376
M.-L. Dubernet, M. H. Alexander, Y. A. Ba, N. Balakrishnan, C. Balanca, C. Ceccarelli, J. Cernicharo, F. Daniel, F. Dayou, M. Doronin, F. Dumouchel, A. Faure, N. Feautrier, D. R. Flower, A. Grosjean, P. Halvick, J. Klos, F. Lique, G. C. McBane, S. Marinakis, N. Moreau, R. Moszynski, D. A. Neufeld, E. Roueff, P. Schilke, A. Spielfiedel, P. C. Stancil, T. Stoecklin, J. Tennyson, B. Yang, A.-M. Vasserot, and L. Wiesenfeld, ``BASECOL2012: A collisional database repository and web service within the Virtual Atomic and Molecular Data Centre (VAMDC),” Astron. Astrophys. 553, A50 (2013).
G. J. Ferland, R. L. Porter, P. A. M. van Hoof, R. J. R. Williams, N. P. Abel, M. L. Lykins, G. Shaw, W. J. Henney, and P. C. Stancil, “The 2013 Release of Cloudy,” Revista Mexicana de Astronomia y Astrofisica 49, 137 (2013); arXiv: 1302.4485
S. Fonseca dos Santos, N. Balakrishnan, R. C. Forrey, and P. C. Stancil, ``Vibration- vibration and vibration-translation energy transfer in H2-H2 collisions: a critical test of experiment with full-dimensional quantum dynamics,” J. Chem. Phys. 138, 104302 (2013).
M. R. Geller, J. M. Martinis, A. T. Sornborger, P. C. Stancil, E. J. Pritchett, and A. Galiautdinov, ``Universal quantum simulation with pre-threshold superconducting qubits: Single-excitation subspace method,” Phys. Rev. X, submitted (10/16/2012); arXiv:1210.5260
H. You, M. R. Geller, and P. C. Stancil, ``Simulating the Transverse Ising Model on a Quantum Computer: error correction with the surface code,” Phys. Rev. A 87, 032341 (2013); arXiv:1210.0113
B. Yang, P. C. Stancil, R. C. Forrey, S. Fonseca dos Santos, and N. Balakrishnan, ``Zero- energy resonances of hydrogen diatom isotopologs: tuning quasiresonant transitions in vibration space,” Phys. Rev. Lett. 109, 233201 (2012).
W. el-Qadi and P. C. Stancil, ``Photodissociation of CN,” Astrophys. J. 779, 970 (2013)
Benhui Yang, M. Nagao, S. Wasu, M. Kimura, and P. C. Stancil, ``Rotational quenching of rotationally-excited H2O in collisions with He,” Astrophys. J. 765, 77, (2013); arXiv: 1302.3916
Y. B. Shi, P. C. Stancil, and J. G. Wang, ``On the X 2Σ+ rovibrational spectrum of LiH.” Astron. Astrophys. 551, A140 (2013).
Stancil J. L. Nolte, P. C. Stancil, H.-P. Liebermann, R. J. Buenker, Y. Hui, and D. R. Schultz, ``Final-state-resolved charge exchange in C5+ collisions with H,” J. Phys. B 45, 245202 (2012).
Y. Wu, P. C. Stancil, D. R. Schultz, Y. Hui, H.-P. Liebermann, P. Funke, R. J. Buenker, ``Theoretical investigation of total and state-dependent charge exchange in O6+ collisions with atomic hydrogen,” J. Phys. B 45, 235201 (2012).
G. Shaw, S. K. Ghosh, G. J. Ferland, P. A. M. van Hoof, J. A. Baldwin, W. J. Henney, E. W. Pellegrini, R. L. Porter, R. J. R. Williams, P. C. Stancil, and N. P. Abel, “Variation of Polycyclic Aromatic Hydrocarbon abundances across the Orion Bar,” Astrophys. J., submitted (Dec. 17, 2011), resubmitted (April 23, 2013).
J. L. Nolte, P. C. Stancil, T.-G. Lee, N. Balakrishnan, and R. C. Forrey, ``Rovibrational quenching rate coefficients of HD in collisions with He,” Astrophys. J. 744, 62 (2012).
W. el-Qadi, R. C. Forrey, B. Yang, P. C. Stancil, and N. Balakrishnan, “Cold collisions of highly rotational-excited CO2 with He: the prospects for cold chemistry with super rotors,” Phys. Rev. A 84, 054701 (2011)
N. C. Sterling and P. C. Stancil, ``Atomic data for neutron-capture elements III. Charge transfer rate coefficients for low-charge ions of Ge, Se, Br, Kr, Rb, and Xe,” Astron. Astrophys. 535, 117 (2011).
Y. Wu, P. C. Stancil, H.-P. Liebermann, P. Funke, S. N. Rai, R. J. Buenker, D. R. Schultz, Y. Hui, I., N. Draganic, and C. C. Havener, ``Theoretical investigation of charge transfer between N6+ and atomic hydrogen,” Phys. Rev. A 84, 022711 (2011).
C. D. Gay, N. P. Abel, R. L. Porter, P. C. Stancil, G. J. Ferland, G. Shaw, P. A. M. van Hoof, and R. J. R. Williams, ``Rovibrationally-Resolved Direct Photodissociation through the Lyman and Werner Transitions of H2 for FUV/X-ray Irradiated Environments,'' Astrophys. J. 746, 78 (2012).
S. Fonseca dos Santos, B. Naduvalath, S. Lepp, G. Quemener, R. C. Forrey, R J. Hinde, and P. C. Stancil, ``Quantum dynamics of rovibrational transitions in H2-H2 collisions: Internal energy and rotational angular momentum conservation effects,'' J. Chem. Phys.134, 214303 (2011).
C. D. Gay, P. C. Stancil, S. Lepp, and A. Dalgarno, ``The Highly Deuterated Chemistry of the Early Universe," Astrophys. J. 735, 44 (2011).
S. Miyake, C. D. Gay, and P. C. Stancil, “Rovibrationally-resolved photodissociation of HeH+,” Astrophys. J. 735, 21 (2011).
Stancil N. Balakrishnan, G. Quemener, R. C. Forrey, R. J. Hinde, and P. C. Stancil,”Full-dimensional quantum dynamics calculations of H2-H2 collisions,'' J. Chem. Phys. 134, 014301 (2010).
B. Yang, R. C. Forrey, P. C. Stancil, and N. Balakrishnan, “Complex scattering lengths for ultracold He collisions with rotationally-excited linear and non-linear molecules,” Phys. Rev. A 82, 052711 (2010).
B. Yang, P. C. Stancil, N. Balakrishnan, and R. C. Forrey, “Rotational quenching of CO due to H2 collisions,” Astrophys. J. 718, 1062 (2010); astro-ph/1004.3923.
R. Ali, P. A. Neill, P. Beiersdorfer, C. L.Harris, D. R. Schultz, and P. C. Stancil, “Critical Test of Simulations of Charge-exchanged-induced X-ray Emission in the Solar System”, Astrophys. J. Letters 716, L95 (2010), astro-ph/1005.2599.
Y. Hui, D. R. Schultz, V. Kharchenko, A. Bhardwaj, G. Branduardi-Raymont, P. C. Stancil, T. E. Cravens, C. M. Lisse, and A. Dalgarno, “Comparative Analysis and Variability of the Jovian X-ray Spectra Detected by the Chandra and XMM-Newton Observatories,” J. Geophys. Res. A 115, 07102 (2010).
S. Miyake, P. C. Stancil, H. R. Sadeghpour, A. Dalgarno, B. M. McLaughlin, and R. C. Forrey, “Resonant H- Photodetachment: Enhanced Photodestruction and Consequences for Radiative Feedback,” Astrophys. J. Letters 709, L168 (2010).
J. L. Nolte, B. H. Yang, P. C. Stancil, T.-G. Lee, N. Balakrishnan, R. C. Forrey, and A. Dalgarno, “Isotope effects in complex scattering lengths for He collisions with molecular hydrogen,” Phys. Rev. A 81, 014701 (2010).
Y. Hui, D. R. Schultz, V. A. Kharchenko, P. C. Stancil, T. E. Cravens, C. M. Lisse, and A. Dalgarno, “The ion-induced charge-exchange X-ray emission of the Jovian Auroras: Magnetospheric or solar wind origin?,” Astrophys. J. Letters 702, L158 (2009).
Y. Wu, Y. Y. Qi, S. Y. Zou, J. G. Wang, Y. Li, R. J. Buenker, and P. C. Stancil, “Quantum-Mechanical Calculations of Charge Transfer in Collisions of O3+ with He,” Phys. Rev. A 79, 062711 (2009).
B. H. Yang and P. C. Stancil, “Rotational Quenching of CO2 by Collisions with He Atoms,” J. Chem. Phys. 130, 134319 (2009).
G. Shaw, G.J. Ferland, W.J. Henney, P.C. Stancil, N.P. Abel, E.W. Pellegrini, J.A. Baldwin, and P.A.M. van Hoof, "Rotational Warm Molecular Hydrogen in the Orion Bar," Astrophys. J. 701, 677 (2009).
B. H. Hosseini, P. F. Weck, H. R. Sadeghpour, K. Kirby, and P. C. Stancil, "Photodissociation dynamics of lithium chloride: Contribution of interferometric predissociation," J. Chem. Phys. 130, 054308 (2009).
C. Y. Lin, P. C. Stancil, H.-P. Liebermann, P. Funke, and R. J. Buenker, "Inelastic processes in collisions of Na(3s,3p) with He at thermal energies," Phys. Rev. A 78, 052706 (2008).
V. Kharchenko, A. Bhardwaj, A. Dalgarno, D. R. Schultz, and P. C. Stancil, "Modeling Spectra of the North and South Jovian X-ray Auroras, " J. Geophys. Res. 113, 8229 (2008).
N. P. Abel, S. R. Federman, and P. C. Stancil, "The Effects of Doubly Ionized Chemistry on SH+ and S2+ Abundances in X-ray Dominated Regions, " Astrophys. J. 675, L81 (2008).
G. Shaw, G.J. Ferland, N.P. Abel, P.C. Stancil, and P.A.M. van Hoof, "Molecular hydrogen in star-forming regions: implementation of its micro-physics in Cloudy," Astrophys. J. 624, 794 (2005).
D. W. Savin, P. S. Krstic, Z. Haiman, and P. C. Stancil, "Rate Coefficients for H+ + H2 -> H + H2+ Charge Transfer and some Cosmological Implications," Astrophys. J. 606, L167 (2004).
S. Lepp, P. C. Stancil, and A. Dalgarno, "Atomic and Molecular Processes in the Early Universe," J. Phys. B 35, R57 (2002).