. Author manuscript; available in PMC: 2012 Sep 1.

Published in final edited form as: Anal Chem. 2011 Jul 26;83(17):6704–6712. doi: 10.1021/ac201175a

Table 3.

Summary of the atomic compositions for 14nm AuNP-C16 COOH-SAM measured from XPS and calculated from flat Au data of XPS and SESSA at various modeling conditions and photoelectron emission angles. Also shown is the ΣX_r²_(N*) when the standard deviations of the experimental measurements are included.

	XPS (atomic %)					SESSA (atomic %)
	AuNP		Flat Au		Flat Au	Flat Au
	AuNP		Flat Au		Flat Au	RSA = 1.05 1.1Å/CH₂; layer		RSA= 1.06 0.9Å/CH₂; layer		RSA = 1.03 0.9Å/CH₂; layer
Photoelectron Line	α=0°		α=55°		α=5° to 85° (geometric correction)	α=45°	α=5° to 85° (geometric correction)
Photoelectron Line	%	SD	%	SD	α=5° to 85° (geometric correction)	CH₂-contamination = 1.5Å			No contamination
C 1s	64.9	1.1	64.9	0.4	62.1	61.2	63.1	64.7	58.2	59.1
Au 4f	21.6	0.4	19.9	0.6	22.6	25.2	22.1	21.5	23.5	24.4
O 1s	11.4	1.0	13.9	1.0	13.6	11.6	13.0	11.8	16.1	14.3
S 2p	2.1	0.3	1.9	0.1	1.7	2.0	1.9	1.9	2.1	2.2
ΣX_r²_(N)	0.0^a		0.76^b		0.64^c	0.81^d	0.29^e	0.03^e	2.14^e	1.62^e
ΣX_r²_{(N*) + (SD)}	0.15		0.59		0.52	0.91	0.25	0.14	2.80	1.24
ΣX_r²_{(N*) − (SD)}	0.15		1.30		1.13	1.02	0.67	0.22	3.93	2.39

= ΣX_r²_(N) comparing the average XPS AuNP composition to itself.

= ΣX_r²_(N) comparing the average XPS AuNP composition with the average XPS flat Au composition at a 55° photoelectron emission angle.

= ΣX_r²_(N) comparing the average XPS AuNP composition with the corrected XPS flat Au composition weighed and summed from the XPS compositions at 9 photoelectron emission angles.

= ΣX_r²_(N) comparing the average XPS AuNP composition with the SESSA flat Au composition at a 45° photoelectron emission angle (RSA=1.05, 1.1Å/CH₂ layer, and 1.5Å CH₂-contamination).

= ΣX_r²_(N) comparing the average XPS AuNP composition with the SESSA flat Au composition weighed and summed from the SESSA compositions at 9 photoelectron emission angles (RSA=1.05, 1.06 or 1.03; CH₂-group thickness = 1.1 or 0.9Å; and with or without 1.5Å CH₂-contamination).

The values for ΣX_r²_(N*) compare the AuNP’s average XPS% plus its standard deviation (ΣX_r²_(N*)+(SD)) or minus its standard deviation (ΣX_r²_(N*)−(SD)) with the other composition values described above (a through e).