C O N T E N T S
i i n t r o d u c t i o n 1
1 t h e c o l d a n d u lt r a c o l d r e g i m e 3
1.1 General consideration . . . 3
1.2 Interest and range of application . . . 5
2 c o o l i n g a n d t r a p p i n g at o m s a n d m o l e c u l e s 7 2.1 Experimental and theoretical achievements . . . 7
2.2 Ion-atom hybrid traps . . . 11
2.2.1 The Heidelberg experiment . . . 14
3 a n i o n s 19 3.1 Anions in the cold and ultracold domain . . . 19
3.2 Definition and properties . . . 20
3.3 Reactivity: detachment processes . . . 24
ii t h e o r e t i c a l b a c k g r o u n d 31 4 e l e c t r o n i c s t r u c t u r e 33 4.1 The molecular Schrödinger equation . . . 33
4.2 The Born Oppenheimer approximation . . . 34
4.3 The independent electron approximation . . . 37
4.4 The Hartree Fock method . . . 38
4.4.1 The mean field approach . . . 38
4.4.2 The Roothan equation . . . 40
4.5 Electron correlation and post-HF methods . . . 41
4.5.1 Configuration interaction (CI) . . . 42
4.5.2 Multi-configuration self consistent field (MCSCF) . 45 4.5.3 Multi-reference configuration interaction (MRCI) . 47 4.5.4 Perturbation methods (MPn) . . . 49
4.5.5 Coupled cluster approach (CC) . . . 50
4.6 The basis set . . . 52
4.6.1 Tempered diffuse functions . . . 54
4.6.2 Basis set superposition error . . . 54
4.7 Spin orbit coupling and relativistic effects . . . 56
4.8 Group theory . . . 59
5 n u c l e a r d y na m i c s 67 5.1 Capture model . . . 68
5.2 The close coupling method . . . 71
5.3 The Landau-Zener and Rosen-Zener-Demkov model . . . 75
ix
x c o n t e n t s
iii r e s u lt s 77
6 t h e m o h− m o l e c u l a r s y s t e m 79
6.1 Molecular structure . . . 79
6.2 Vibrational frequencies . . . 92
6.3 The Rb-OH− case . . . 96
6.3.1 Ground state collision: Rb(2S)+OH− . . . 98
6.3.2 Excited state collision: Rb(2P)+OH− . . . 113
6.3.3 Total loss rate and comparison with experiment . . 133
6.4 Excited states of alkaline earth hydroxide anions . . . 136
6.5 Conclusion and outlook . . . 139
7 h y d r at e d h y d r o x i d e a n i o n c l u s t e r s: o h(h2o)−n 143 7.1 Generalities and motivation . . . 143
7.2 The hydrated hydroxide anion . . . 145
7.3 Reactivity . . . 150
7.3.1 Collision with H atoms . . . 150
7.3.2 Collision with Rb atoms . . . 163
7.4 Conclusion and outlook . . . 177
8 t h e r b-c− 2 a n d l i-c− 2 m o l e c u l a r s y s t e m s 181 8.1 Motivations . . . 181
8.2 Potential energy surfaces . . . 182
8.3 Reactive collisions . . . 186
8.4 Inelastic cross sections . . . 190
8.5 Conclusion and outlook . . . 196
iv g e n e r a l c o n c l u s i o n a n d p e r s p e c t i v e s 199 v a p p e n d i x 207 a a p p e n d i x a 209 a.1 Non adiabatic coupling matrix element for Rb+OH− . . . 209
a.2 Spin orbit coupling in the Rb-C−2 complex . . . 210
a.3 Harmonic frequencies . . . 212
b a p p e n d i x b 217
b i b l i o g r a p h y 229
