### Abstract

New accurate ground-state potential energy curves (PEC) for the ^{4}HeH ^{+}, ^{4}HeD ^{+}, ^{3}HeH ^{+}, and ^{3}HeD ^{+} isotopologues are calculated with 600 explicitly correlated Gaussian (ECG) functions with shifted centers in the range between R = 0.35 a _{0} and 145 a _{0}. The calculations include the adiabatic corrections (AC). The absolute accuracy of all Born-Oppenheimer (BO) PEC points is better than 0.0018 cm ^{-1} and it is better than 0.0005 cm ^{-1} for the ACs. With respect to the very recent BO PEC calculations performed by Pachucki with 20 000 generalized Heitler-London explicitly correlated functions [K. Pachucki, Phys. Rev. A 85, 042511 (2012)]10.1103/PhysRevA.85.042511, the present energy calculated at R = 1.46 a _{0} (a point near the BO equilibrium distance) lies above by only 0.0012 cm ^{-1}. Using Pachuckis BO energy at the equilibrium distance of R = 1.463 283 a _{0}, and the adiabatic corrections calculated in this work for the ^{4}HeH ^{+}, ^{4}HeD ^{+}, ^{3}HeH ^{+}, and ^{3}HeD ^{+} isotopologues, the following values are obtained for their PEC depths: 16 448.99893 cm ^{-1}, 16 456.86246 cm ^{-1}, 16 451.50635 cm ^{-1}, and 16 459.36988 cm ^{-1}, respectively. We also calculate the rovibrational (rovib) frequencies for the four isotopologues using the BO PEC of Pachucki augmented with the present ACs. The improvements over the BO+AC PEC of Bishop and Cheung (BC) [J. Mol. Spectrosc. 75, 462 (1979)]10.1016/0022-2852(79)90090-0 are 1.522 cm ^{-1} at R = 4.5 a _{0} and 0.322 cm ^{-1} at R . To partially account for the nonadiabatic effects in the rovib calculations an effective reduced-mass approach is used. With that, the present ^{4}HeH ^{+} rovibrational transitions are considerably improved over the BC transitions as compared with the experimental values. Now the rovibrational transitions near the dissociation limit are as well reproduced by the present calculations as the lower transitions. For example, for the ^{4}HeD ^{+} transitions corresponding to the ν = 13-9 hot bands the results are off from the experimental values by less than 0.023 cm ^{-1}. This confirms high accuracy of the present PECs at larger internuclear separations.

Original language | English (US) |
---|---|

Article number | 164305 |

Journal | The Journal of Chemical Physics |

Volume | 137 |

Issue number | 16 |

DOIs | |

State | Published - Oct 28 2012 |

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### ASJC Scopus subject areas

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

### Cite this

^{+}isotopologues.

*The Journal of Chemical Physics*,

*137*(16), [164305]. https://doi.org/10.1063/1.4759077

**Accurate potential energy curves for HeH ^{+} isotopologues.** / Tung, Wei Cheng; Pavanello, Michele; Adamowicz, Ludwik.

Research output: Contribution to journal › Article

^{+}isotopologues',

*The Journal of Chemical Physics*, vol. 137, no. 16, 164305. https://doi.org/10.1063/1.4759077

^{+}isotopologues. The Journal of Chemical Physics. 2012 Oct 28;137(16). 164305. https://doi.org/10.1063/1.4759077

}

TY - JOUR

T1 - Accurate potential energy curves for HeH + isotopologues

AU - Tung, Wei Cheng

AU - Pavanello, Michele

AU - Adamowicz, Ludwik

PY - 2012/10/28

Y1 - 2012/10/28

N2 - New accurate ground-state potential energy curves (PEC) for the 4HeH +, 4HeD +, 3HeH +, and 3HeD + isotopologues are calculated with 600 explicitly correlated Gaussian (ECG) functions with shifted centers in the range between R = 0.35 a 0 and 145 a 0. The calculations include the adiabatic corrections (AC). The absolute accuracy of all Born-Oppenheimer (BO) PEC points is better than 0.0018 cm -1 and it is better than 0.0005 cm -1 for the ACs. With respect to the very recent BO PEC calculations performed by Pachucki with 20 000 generalized Heitler-London explicitly correlated functions [K. Pachucki, Phys. Rev. A 85, 042511 (2012)]10.1103/PhysRevA.85.042511, the present energy calculated at R = 1.46 a 0 (a point near the BO equilibrium distance) lies above by only 0.0012 cm -1. Using Pachuckis BO energy at the equilibrium distance of R = 1.463 283 a 0, and the adiabatic corrections calculated in this work for the 4HeH +, 4HeD +, 3HeH +, and 3HeD + isotopologues, the following values are obtained for their PEC depths: 16 448.99893 cm -1, 16 456.86246 cm -1, 16 451.50635 cm -1, and 16 459.36988 cm -1, respectively. We also calculate the rovibrational (rovib) frequencies for the four isotopologues using the BO PEC of Pachucki augmented with the present ACs. The improvements over the BO+AC PEC of Bishop and Cheung (BC) [J. Mol. Spectrosc. 75, 462 (1979)]10.1016/0022-2852(79)90090-0 are 1.522 cm -1 at R = 4.5 a 0 and 0.322 cm -1 at R . To partially account for the nonadiabatic effects in the rovib calculations an effective reduced-mass approach is used. With that, the present 4HeH + rovibrational transitions are considerably improved over the BC transitions as compared with the experimental values. Now the rovibrational transitions near the dissociation limit are as well reproduced by the present calculations as the lower transitions. For example, for the 4HeD + transitions corresponding to the ν = 13-9 hot bands the results are off from the experimental values by less than 0.023 cm -1. This confirms high accuracy of the present PECs at larger internuclear separations.

AB - New accurate ground-state potential energy curves (PEC) for the 4HeH +, 4HeD +, 3HeH +, and 3HeD + isotopologues are calculated with 600 explicitly correlated Gaussian (ECG) functions with shifted centers in the range between R = 0.35 a 0 and 145 a 0. The calculations include the adiabatic corrections (AC). The absolute accuracy of all Born-Oppenheimer (BO) PEC points is better than 0.0018 cm -1 and it is better than 0.0005 cm -1 for the ACs. With respect to the very recent BO PEC calculations performed by Pachucki with 20 000 generalized Heitler-London explicitly correlated functions [K. Pachucki, Phys. Rev. A 85, 042511 (2012)]10.1103/PhysRevA.85.042511, the present energy calculated at R = 1.46 a 0 (a point near the BO equilibrium distance) lies above by only 0.0012 cm -1. Using Pachuckis BO energy at the equilibrium distance of R = 1.463 283 a 0, and the adiabatic corrections calculated in this work for the 4HeH +, 4HeD +, 3HeH +, and 3HeD + isotopologues, the following values are obtained for their PEC depths: 16 448.99893 cm -1, 16 456.86246 cm -1, 16 451.50635 cm -1, and 16 459.36988 cm -1, respectively. We also calculate the rovibrational (rovib) frequencies for the four isotopologues using the BO PEC of Pachucki augmented with the present ACs. The improvements over the BO+AC PEC of Bishop and Cheung (BC) [J. Mol. Spectrosc. 75, 462 (1979)]10.1016/0022-2852(79)90090-0 are 1.522 cm -1 at R = 4.5 a 0 and 0.322 cm -1 at R . To partially account for the nonadiabatic effects in the rovib calculations an effective reduced-mass approach is used. With that, the present 4HeH + rovibrational transitions are considerably improved over the BC transitions as compared with the experimental values. Now the rovibrational transitions near the dissociation limit are as well reproduced by the present calculations as the lower transitions. For example, for the 4HeD + transitions corresponding to the ν = 13-9 hot bands the results are off from the experimental values by less than 0.023 cm -1. This confirms high accuracy of the present PECs at larger internuclear separations.

UR - http://www.scopus.com/inward/record.url?scp=84868352809&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84868352809&partnerID=8YFLogxK

U2 - 10.1063/1.4759077

DO - 10.1063/1.4759077

M3 - Article

C2 - 23126708

AN - SCOPUS:84868352809

VL - 137

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 16

M1 - 164305

ER -