Comparison of Magnetic Deflection among Neutral Sodium-Doped Clusters: Na(H₂O)_n, Na(NH₃)_n, Na(MeOH)_n, and Na(DME)_n

Abstract

Using a pulsed Stern–Gerlach deflection experiment, we present the results of a comparative study on the magnetic properties of neutral sodium-doped solvent clusters Na­(Sol) n with n = 1–4 (Sol: H2O, NH3, CH3OH, CH3OCH3). Experimental deflection ratios are compared with values calculated from molecular dynamics simulations. NaNH3 and NaH2O are deflected as a spin 1/2 system, consistent with spin transitions occurring on a time scale significantly longer than 100 μs. For all other clusters, reduced deflection is observed. The observed magnetic deflection behavior is correlated to the number of thermally populated rotational states in the clusters. We discuss that spin–rotational couplings allow for avoided crossings and a reduction in the effective magnetic moment of the cluster. This work attempts to understand the evolution of magnetic properties in isolated weakly bound clusters and is relevant to diamagnetic and paramagnetic species expected to exist in solvated electron systems.

Out-of-focus spatial map imaging of magnetically deflected sodium ammonia clusters

“…6 and the optimal t values are summarised in Table 1 for this work (t SMI ) and our previous study (t slit ), where we used a non-moveable slit to quantify deflection. 5 In Fig. 6, we observe a good agreement between the MD simulations and the experimental data for the different clusters, particularly in the center of the profile around z = AE3 mm.…”

“…The general experimental setup used in this work is similar to setups previously used in our research group. 5,9,35 Hence, only a brief description of the experiment is provided here. Fig.…”

“…36 Subsequently, the sodium-doped clusters passed through a 1 mm diameter skimmer (S2) and entered the deflection chamber, which houses the pulsed Stern-Gerlach (SG) deflector. 5,9 The calibration measurements for out-of-focus SMI were performed with the deflector turned off and an additional final skimmer (S3) of 2 mm diameter (see ESI ‡). For the spatially resolved deflection measurements, the skimmer S3 was removed and replaced with a 25 mm diameter hole to allow for the detection of all deflected clusters.…”

“…Values of t SMI (this work) and t slit from ref 5. for Na(NH 3 ) n , 1 r n r 9 and Na 3 (NH 3 ) n , 1 r n r 2 clusters.…”

“…1,2 The spatial deflection reveals direct information about the time-averaged projection of the magnetic moment on the deflection axis, thereby offering valuable new insights into the size and geometry of the deflected species. [3][4][5][6] For example, magnetic deflection was used to gain information on the geometry of nanoalloys, composed of aluminium, gallium or indium tin clusters, 4 sodium doped solvent clusters, with ammonia, water, methanol or dimethyl ether as a solvent, 5 or the effect of oxidation on the magnetism of cobalt oxide clusters. 6 The original experiment by Stern and Gerlach, measured magnetic deflection by capturing an image of the detector and manually reading the distances of the deflected species from the undeflected position.…”