Embed Size (px)
Citation preview
7/29/2019 Infrared spectrum of hydrochloric acid
http://slidepdf.com/reader/full/infrared-spectrum-of-hydrochloric-acid 1/2
Conc. HCl - a few drops on the bottom of a quartz cuvette Resolution 0.125 cm-1 Nicolet 6700 FT-IR - 16 scans/ Software: Optima
Wavenumbers (cm-1) Wavenumbers (m-1) Spacing in m-1 Wavenumbers (m-1) of the weaker signals Diff. in wavenumbers (m-1)| isotopes Label of the transition (P branch or R branch
3072.82 307282 P(11)
3059.31 305931 1351 P(10)
3045.03 304503 1428 304271 232 P(9)
3030.06 303006 1497 302775 231 P(8)
3014.39 301439 1567 301211 228 P(7)
2998.03 299803 1636 299576 227 P(6)
2980.98 298098 1705 297874 224 P(5)
2963.27 296327 1771 296104 223 P(4)
2944.9 294490 1837 294271 219 P(3)
2925.89 292589 1901 292373 216 P(2)
2906.23 290623 1966 290411 212 P(1)
"Missing line"
2865.08 286508 286300 208 R(0)
2843.61 284361 2147 284156 205 R 1
2821.55 282155 2206 281955 200 R(2)
2798.93 279893 2262 279696 197 R 3
2775.74 277574 2319 277380 194 R(4)
2752.02 275202 2372 275012 190 R(5)
2727.75 272775 2427 272590 185 R(6)
2702.99 270299 2476 R(7)
2677.71 267771 2528 R(8)
J' 4J'+2 Change in wavenumbers in m-1 (for all transitions e
J=1 Δν=ν(R(0))-ν(P(2)) 1 6
J=2 Δν=ν(R(1))-ν(P(3)) 2 10J=3 Δν=ν(R(2))-ν(P(4)) 3 14
J=4 Δν=ν(R(3))-ν(P(5)) 4 18
J=5 Δν=ν(R(4))-ν(P(6)) 5 22
J=6 Δν=ν(R(5))-ν(P(7)) 6 26
J=7 Δν=ν(R(6))-ν(P(8)) 7 30
J=8 Δν=ν(R(7))-ν(P(9)) 8 34
J=9 Δν=ν(R(8))-ν(P(10)) 9 38
*by ν above I mean wavenumbers
J'' 4J''+2 Change in wavenumbers in cm-1 (for all transitions
J=1 Δν=ν(R(1))-ν(P(1)) 1 6
J=2 Δν=ν R 2 -ν P 2 2 10
J=3 Δν=ν(R(3))-ν(P(3)) 3 14
J=4 Δν=ν R 4 -ν P 4 4 18
J=5 Δν=ν(R(5))-ν(P(5)) 5 22
J=6 Δν=ν R 6 -ν P 6 6 26J=7 Δν=ν(R(7))-ν(P(7)) 7 30
J=8 Δν=ν(R(8))-ν(P(8)) 8 34
Pi 3.141592654
m-1 Hz
ν(R(0))=ω+2B' => find ω for HCl 35 284430.2 8.53291E+13
k=[2pi*(3*10^8*wavenumbers in m-1]^2*reduced mass in kg 467.6901869 Lit value in Macquarrie Table 5.1 = 478
k for H37Cl is considered equal to k for H35Cl therefore ω(HCl 35)/ ω(HCl 37)=srqt(μ(HCl 37)/μ(HCl 35))
reduced mass of HCl 35 in amu 0.979568849
reduced mass of HCl 37 in amu 0.981053574
μ(HCl 37)/μ(HCl 35) = 1.001515692
(ω for HCl 37)^2 80778103919
ω for HCl 37 in m-1 284214.8904
ω for HCl 35 - ω for HCl 37 (in m-1) 215.3096109 CLOSE to the values in column E
S translational = (3/2)*R*ln(mol weight in g)+(5/2)RlnT-9.66J/(K*mol) 153.436044
Qrotational=kT hcB'' 20.54868661 hω kT = 13.74145766
Qvibrational=1/(1-e^(-(hω/(kT)))) 1.000001077
Srotational=R(1+lnQrot) 33.44553448
Svibrational=R((hω/(kT)/(e^(hω/(kT))-1)+lnQvib) 0.000131981
Stotal(HCl35)=Strans+Svib+Srot 186.8817105
Lit value http://kinetics.nist.gov/janaf/html/Cl-026.html 186.9
Average B (if harmonic) in m-1 983.222I HCl (kg*m^2) 2.84504E-47
μ HCl 35 in kg 1.62706E-27
μ HCl 37 in kg 1.62953E-27
Bond length HCl 35 in pm 132.2
Bond length HCl 35 lit. value in pm 127.5
Anharmonic
B' in m-1 v=0 in m-1 1007.3
B'' in m-1 (v=1) in m-1 1038.9
I for v=0 in k *m^2 2.69257E-47
I (for v=1) in kg*m^2 2.77704E-47
Bond length (v=0) in pm 128.6
Bond length (v=1) in pm 130.6
k in N/m 467.9
k in N/m lit. value 478
ω for HCl 35 in m-1 284430.2
ω for HCl 37 in m-1 284214.8904
ω for HCl 35 - ω for HCl 37 (in m-1) 215.3096109
S translational in J/(K*mol) 153.436044
Srotational in J/(K*mol) 33.44553448
Svibrational in J/(K*mol) 0.000131981
S total in J/(K*mol) 186.8817105
S total in J/(K*mol) lit. value 186.9
7/29/2019 Infrared spectrum of hydrochloric acid
http://slidepdf.com/reader/full/infrared-spectrum-of-hydrochloric-acid 2/2
so B in m-1 is
983.2222222
2.84504E-47
0.979568849
1.62706E-27 Literature value in MacQuarrie (Table) 5.1
1.32234E-10 127.5 pm
<- bond length in V=1
Really close to the literature value! (above)
Yes, the radius for the v=1 state is larger than the radius for v=0 state
y = 1007.3x
R² = 0.99996so B''=1007.3 m-1
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
0 5 10 15 20 25 30 35 40
W a v
e n u m b e r s d i f f e r e n c e i n m - 1
4J'+2
y = 1038.9x
R² = 0.99997
so B'=1038.9 m-1
0
5000
10000
15000
20000
25000
30000
35000
40000
0 5 10 15 20 25 30 35 40
W a v e n u m b e r s d i f f e r e n c e i n m - 1
4J''+2
