Orbital alignment in N2O photodissociation. I. Determination of all even rank anisotropy parameters

Abstract

We present a general method for determination of the photofragment K=4 state multipoles in an ion imaging experiment. These multipoles are important for determining the full density matrix for any photofragment with j(a)> or =2. They are expressed in terms of laboratory frame anisotropy parameters that have distinct physical origins and possess characteristic angular distributions. The explicit expression for the (2+1) resonant multiphoton ionization absorption signal for the case of arbitrarily polarized probe light is derived and a procedure for isolation of the rank-4 state multipoles from all others is shown. This treatment is applied to the case of O((1)D) produced in the 193 nm photodissociation of N2O. The results show nonzero values for all K=4 anisotropy parameters, indicating the complexity of the photodissociation dynamics in this system.

Single-field slice-imaging with a movable repeller: Photodissociation of N2O from a hot nozzle

“…As observed previously, [14][15][16][17][18][19][20][21][22] Since the corresponding sibling N 2 (J) photofragments do not show this effect, e.g., in Fig. 6 the angular distribution is maximum at θ = 0 o , this has been attributed to a preferential alignment of the O( 1 D 2 ) atomic orbital with respect to the recoil velocity.…”

“…Also due to the large change in NNO angle upon photoexcitation, N 2 photoproducts are formed with a large amount of rotational excitation (60 < J < 80). In recent years N 2 O has been subject to a number of high resolution experiments [13][14][15][16] using VMI, [17][18][19][20][21][22] as well as high level theoretical calculations. [23][24][25][26][27][28][29][30][31][32] In the most recent VMI study of Suzuki and coworkers, 22 the authors ionized individual rotational states of the N 2 photoproduct.…”

Photofragment angular momentum distributions from oriented and aligned polyatomic molecules: beyond the axial recoil limit

“…This formalism, and an equivalent molecular-frame formalism by Rakitzis and Zare [3], was used to successfully describe the photofragment polarization measured from the photodissociation of a number of diatomic molecules (well described by the axial recoil approximation) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. More recently, photofragment polarization has been measured from the photodissociation of polyatomic molecules, for which the axial recoil approximation breaks down [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. The polarization measurements can be fitted with the same polarization parameter basis functions (as they form a complete basis), however the interpretation of the values of the polarization parameters is no longer straightforward or well-understood.…”

The photodissociation dynamics of ozone at 193nm: An O(D21) angular momentum polarization study

“…In practice, the f K(q, q ' ; v) dynamical factors are usually recast in a variety of different (but parametrically equivalent) ways, including the polariza tion parameters of Rakitzis and Zare and the polariza tion anisotrop^y parameters of Vasyutinskii and co-workers.4, 23,35,38 In the present work we use the latter set of parameters.…”