Table 1. Calculated and Experimental Frequencies of TO, LO, and E₂^H modes for GaP ZB, WZ, and TSL^a.

	TO (cm–1)			LO (cm–1)			E2H (cm–1)
	ZB	WZ	TSL	ZB	WZ	TSL	WZ	TSL
theory	362.2	360.1	361.6	391.9 (396.5)	391.2	391.7	354.7	355.6
exp.	366.2	363.0	365.5	402.6	400.2	402.4	356.3	357.3

^aExperimental frequencies refer to the samples of Figure 2c,d. The TSL period is 9 nm. The scattering configuration used both for experiments and calculations is x̅(zz)x for the TO and LO modes and x̅(yy)x for the E₂^H. The error on the experimental values is ±0.5 cm^–1. The value between parentheses for the calculated LO frequency of the ZB has been obtained by renormalization of the non-analytical corrections using the experimental value of the dielectric constant.