Structure determination of alkali trimers on helium nanodroplets through laser-induced Coulomb explosion

TY - JOUR

T1 - Structure determination of alkali trimers on helium nanodroplets through laser-induced Coulomb explosion

AU - Kranabetter, Lorenz

AU - Kristensen, Henrik H

AU - Schouder, Constant A

AU - Stapelfeldt, Henrik

N1 - © 2024 Author(s). Published under an exclusive license by AIP Publishing.

PY - 2024/4

Y1 - 2024/4

N2 - Alkali trimers, Ak 3, located on the surface of He nanodroplets are triply ionized following multiphoton absorption from an intense femtosecond laser pulse, leading to fragmentation into three correlated Ak + ions. Combining the information from threefold covariance analysis of the emission direction of the fragment ions and their kinetic energy distributions P(E kin), we find that Na 3, K 3, and Rb 3 have an equilateral triangular structure, corresponding to that of the lowest lying quartet state A 2 ′ 4 , and determine the equilibrium bond distance R eq(Na 3) = 4.65 ± 0.15 Å, R eq(K 3) = 5.03 ± 0.18 Å, and R eq(Rb 3) = 5.45 ± 0.22 Å. For K 3 and Rb 3, these values agree well with existing theoretical calculations, while for Na 3, the value is 0.2-0.3 Å larger than the existing theoretical results. The discrepancy is ascribed to a minor internuclear motion of Na 3 during the ionization process. In addition, we determine the distribution of internuclear distances P(R) under the assumption of fixed bond angles.

AB - Alkali trimers, Ak 3, located on the surface of He nanodroplets are triply ionized following multiphoton absorption from an intense femtosecond laser pulse, leading to fragmentation into three correlated Ak + ions. Combining the information from threefold covariance analysis of the emission direction of the fragment ions and their kinetic energy distributions P(E kin), we find that Na 3, K 3, and Rb 3 have an equilateral triangular structure, corresponding to that of the lowest lying quartet state A 2 ′ 4 , and determine the equilibrium bond distance R eq(Na 3) = 4.65 ± 0.15 Å, R eq(K 3) = 5.03 ± 0.18 Å, and R eq(Rb 3) = 5.45 ± 0.22 Å. For K 3 and Rb 3, these values agree well with existing theoretical calculations, while for Na 3, the value is 0.2-0.3 Å larger than the existing theoretical results. The discrepancy is ascribed to a minor internuclear motion of Na 3 during the ionization process. In addition, we determine the distribution of internuclear distances P(R) under the assumption of fixed bond angles.

U2 - 10.1063/5.0200389

DO - 10.1063/5.0200389

M3 - Journal article

C2 - 38557840

SN - 0021-9606

VL - 160

JO - The Journal of Chemical Physics

JF - The Journal of Chemical Physics

IS - 13

M1 - 131101

ER -