### Abstract

Calibration-quality ab initio adiabatic potential energy surfaces (PES) have been determined for all isotopologues of the molecular ion H3+. The underlying Born-Oppenheimer electronic structure computations used optimized explicitly correlated shifted Gaussian functions. The surfaces include diagonal Born-Oppenheimer corrections computed from the accurate electronic wave functions. A fit to the 41 655 ab initio points is presented which gives a standard deviation better than 0.1cm ^{-1} when restricted to the points up to 6000cm ^{-1} above the first dissociation asymptote. Nuclear motion calculations utilizing this PES, called GLH3P, and an exact kinetic energy operator given in orthogonal internal coordinates are presented. The ro-vibrational transition frequencies for H3+, H _{2}D, and HD2+ are compared with high resolution measurements. The most sophisticated and complete procedure employed to compute ro-vibrational energy levels, which makes explicit allowance for the inclusion of non-adiabatic effects, reproduces all the known ro-vibrational levels of the H3+ isotopologues considered to better than 0.2cm ^{-1}. This represents a significant (order-of-magnitude) improvement compared to previous studies of transitions in the visible. Careful treatment of linear geometries is important for high frequency transitions and leads to new assignments for some of the previously observed lines. Prospects for further investigations of non-adiabatic effects in the H3+ isotopologues are discussed. In short, the paper presents (a) an extremely accurate global potential energy surface of H3+ resulting from high accuracy ab initio computations and global fit, (b) very accurate nuclear motion calculations of all available experimental line data up to 16 000cm ^{-1}, and (c) results suggest that we can predict accurately the lines of H3+ towards dissociation and thus facilitate their experimental observation.

Original language | English |
---|---|

Article number | 184303 |

Journal | The Journal of Chemical Physics |

Volume | 136 |

Issue number | 18 |

DOIs | |

Publication status | Published - May 14 2012 |

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### ASJC Scopus subject areas

- Physics and Astronomy(all)
- Physical and Theoretical Chemistry

### Cite this

_{3}

^{+}and its isotopologues.

*The Journal of Chemical Physics*,

*136*(18), [184303]. https://doi.org/10.1063/1.4711756

**Calibration-quality adiabatic potential energy surfaces for H _{3} ^{+} and its isotopologues.** / Pavanello, Michele; Adamowicz, Ludwik; Alijah, Alexander; Zobov, Nikolai F.; Mizus, Irina I.; Polyansky, Oleg L.; Tennyson, Jonathan; Szidarovszky, Tamás; Császár, A.

Research output: Contribution to journal › Article

_{3}

^{+}and its isotopologues',

*The Journal of Chemical Physics*, vol. 136, no. 18, 184303. https://doi.org/10.1063/1.4711756

_{3}

^{+}and its isotopologues. The Journal of Chemical Physics. 2012 May 14;136(18). 184303. https://doi.org/10.1063/1.4711756

}

TY - JOUR

T1 - Calibration-quality adiabatic potential energy surfaces for H 3 + and its isotopologues

AU - Pavanello, Michele

AU - Adamowicz, Ludwik

AU - Alijah, Alexander

AU - Zobov, Nikolai F.

AU - Mizus, Irina I.

AU - Polyansky, Oleg L.

AU - Tennyson, Jonathan

AU - Szidarovszky, Tamás

AU - Császár, A.

PY - 2012/5/14

Y1 - 2012/5/14

N2 - Calibration-quality ab initio adiabatic potential energy surfaces (PES) have been determined for all isotopologues of the molecular ion H3+. The underlying Born-Oppenheimer electronic structure computations used optimized explicitly correlated shifted Gaussian functions. The surfaces include diagonal Born-Oppenheimer corrections computed from the accurate electronic wave functions. A fit to the 41 655 ab initio points is presented which gives a standard deviation better than 0.1cm -1 when restricted to the points up to 6000cm -1 above the first dissociation asymptote. Nuclear motion calculations utilizing this PES, called GLH3P, and an exact kinetic energy operator given in orthogonal internal coordinates are presented. The ro-vibrational transition frequencies for H3+, H 2D, and HD2+ are compared with high resolution measurements. The most sophisticated and complete procedure employed to compute ro-vibrational energy levels, which makes explicit allowance for the inclusion of non-adiabatic effects, reproduces all the known ro-vibrational levels of the H3+ isotopologues considered to better than 0.2cm -1. This represents a significant (order-of-magnitude) improvement compared to previous studies of transitions in the visible. Careful treatment of linear geometries is important for high frequency transitions and leads to new assignments for some of the previously observed lines. Prospects for further investigations of non-adiabatic effects in the H3+ isotopologues are discussed. In short, the paper presents (a) an extremely accurate global potential energy surface of H3+ resulting from high accuracy ab initio computations and global fit, (b) very accurate nuclear motion calculations of all available experimental line data up to 16 000cm -1, and (c) results suggest that we can predict accurately the lines of H3+ towards dissociation and thus facilitate their experimental observation.

AB - Calibration-quality ab initio adiabatic potential energy surfaces (PES) have been determined for all isotopologues of the molecular ion H3+. The underlying Born-Oppenheimer electronic structure computations used optimized explicitly correlated shifted Gaussian functions. The surfaces include diagonal Born-Oppenheimer corrections computed from the accurate electronic wave functions. A fit to the 41 655 ab initio points is presented which gives a standard deviation better than 0.1cm -1 when restricted to the points up to 6000cm -1 above the first dissociation asymptote. Nuclear motion calculations utilizing this PES, called GLH3P, and an exact kinetic energy operator given in orthogonal internal coordinates are presented. The ro-vibrational transition frequencies for H3+, H 2D, and HD2+ are compared with high resolution measurements. The most sophisticated and complete procedure employed to compute ro-vibrational energy levels, which makes explicit allowance for the inclusion of non-adiabatic effects, reproduces all the known ro-vibrational levels of the H3+ isotopologues considered to better than 0.2cm -1. This represents a significant (order-of-magnitude) improvement compared to previous studies of transitions in the visible. Careful treatment of linear geometries is important for high frequency transitions and leads to new assignments for some of the previously observed lines. Prospects for further investigations of non-adiabatic effects in the H3+ isotopologues are discussed. In short, the paper presents (a) an extremely accurate global potential energy surface of H3+ resulting from high accuracy ab initio computations and global fit, (b) very accurate nuclear motion calculations of all available experimental line data up to 16 000cm -1, and (c) results suggest that we can predict accurately the lines of H3+ towards dissociation and thus facilitate their experimental observation.

UR - http://www.scopus.com/inward/record.url?scp=84862891807&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84862891807&partnerID=8YFLogxK

U2 - 10.1063/1.4711756

DO - 10.1063/1.4711756

M3 - Article

VL - 136

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 18

M1 - 184303

ER -